Local police were after another bad guy: blue lights, bold manoeuvres, 100mph-plus speeds. Had she opened the window of her mum’s flat, on the ninth floor of a tower block in Reading, Bryony Morgan might have heard the wail of sirens on the nearby dual carriageway. As it was, on this chilly night in February 2013, she went to run a bath. Bryony’s boyfriend, Matthew, had gone out on a quick errand. He was two years older, 19 to her 17, and she was in love with him – properly lose-your-mind, lose-sleep in love. She wanted them to have kids and had stashed a pregnancy test kit in her bedroom. Police chases? As much as Bryony ever thought about them, it was to wonder, as hazily as any of us – how else would police stop the bad guys?

Out on the Reading bypass, the chase was pushing into a fourth minute. It had begun when an officer from the district police force, Thames Valley, pulled up at some traffic lights behind an old red Ford Fiesta. On a hunch, the officer checked the Fiesta’s registration and learned that the car was linked to a Reading man in his 30s named Brendan Wooff, a serial offender well known to local police. The officer was about to switch on his flickering blues, he later told an inquiry, as a signal for the car in front to pull over, when the traffic lights changed and the Fiesta accelerated away. “Vehicle making off,” the officer radioed to his station’s control room. “Speed five-zero [50] miles per hour.” He gave chase. Everything escalated quickly after that – 60, 80, 100mph.

Red lights were run. More police joined the chase, including a trained pursuit driver who was beginning to catch up with the original officer when the driver of the speeding Fiesta lost control. Coming around a slight bend and finding its path blocked by another vehicle, the car swerved, struck the central reservation and flipped, shedding smoke and debris. The driver was thrown out of his side window and on to the asphalt. The trained pursuit car, boxed in by other police vehicles, unable to dodge, ran him over. It was not Wooff, Thames Valley officers learned, when they began the work of identifying the dead driver in the road. This was Matthew Seddon, a 19-year-old labourer – Bryony Morgan’s boyfriend. A secondhand-car enthusiast who liked to fix up and resell old bangers, Matthew had bought Wooff’s Fiesta that same afternoon.

Start to finish, this chase lasted 4 min 22 sec. The aftermath of a chase gone wrong, though, is measured not in minutes and seconds, but in months and years. As far into the future as 2018 there would still be judges, investigators, witnesses, relatives and their claimant lawyers, constables, police drivers, control-room officers and their silks, all picking over the momentary choices made by Matthew Seddon and Thames Valley police on those Reading roads, everyone trying to slow down and scrutinise 270 seconds of wild driving to work out what happened.

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This is the story of Matthew’s family as that investigation was underway between 2013 and 2018. The case would challenge, in the end, the very nature of the contract that binds British police to the citizens they superintend. This is also the story of the police chase itself – a crimestopping tool we take for granted, hardly think about, but maybe should, given the moral and legal dilemmas that result when we send even very well-trained police officers after suspects who intend to try their luck till they escape, run out of fuel or crash.

Between Matthew Seddon’s death in 2013 and the end of a full inquiry into what happened, late last year, thousands more police chases were launched. Most fizzled out quickly or were abandoned. Many concluded with arrests. Some resulted in serious injury or death. According to figures compiled by the police-complaints office and by the charity Inquest, at least 93 people died in chases in England and Wales during this period. Drivers, passengers and pedestrians were killed. Twice, there were unthinkable disasters involving children; also a long period of public panic about teenage criminals on mopeds – some of them little more than children themselves as they wove around city streets evading police. There would be tyre-streaked roads. Yellow tape. Left-behind partners and relatives, the 17-year-old Bryony Morgan among them.

Matthew had been gone almost two hours when Bryony looked out of her window and saw a police car parking outside. It was 1am. All the officers could tell her was that there had been a collision on the bypass and that her boyfriend was dead. She called Matthew’s brother, Sean, who spoke to Thames Valley police to find out more, before composing himself and calling their mum. Bryony waited out the night with her mother and, in the morning, walked the short distance to the crash site. Faced with cones, collision debris and news cameras, she hung back. There were spray-painted lines on the road that marked the presumed trajectories of the cars. The crumpled red Fiesta was still there, wing touching the kerb and, around it, several police cars had been left in staggered file: wherever they had stopped when their shaken drivers first clambered out to learn exactly who they had been chasing.

As a rough rule, for about a century, we have asked that our police officers go after anybody if the prompt is there – petty criminals, wrong-lookers or serial stabbers alike. Back in 1905, officers in Lancashire were praised for their quick thinking when they persuaded a civilian in one of the new motorcars to take them after a suspect in a horsedrawn hansom. There were deaths recorded throughout the 1920s and 30s, of fleeing suspects (the members of a Gloucester gang pinned under an overturned Morris), of passengers (a barmaid flung from a car in flight in Worsley), of random bystanders. When a Wolverhampton patrolman hit and killed a cyclist in 1937, mid-pursuit, he explained he was under orders that night to speed after any cars that were speeding. By 1970, when police went after a bus in Somerset to interview one of its passengers, the informal thinking about pursuits would have been well entrenched – “that the cops chase the bad guys at all costs,” as the American criminologist Geoffrey Alpert has phrased it. The bus went off a steep verge and toppled, injuring 16 and killing one.

Since the early 2000s, deaths involving speeding police vehicles have been summarised each spring in a report compiled by a police-complaints watchdog, currently known as the Independent Office of Police Complaints, or the IOPC. Taken together, these brisk annual abstracts (“Elderly driver … lost control … unrelated vehicle … five pedestrians and one cyclist … discharged from hospital but died at home”) tend to suggest that occasional disasters are unavoidable, a necessary tax in return for proper crime suppression. Alpert has remarked on a curious aspect of the police chase: how little the public tend to question it.

In the 1980s, Alpert was invited by the UK government to consult on the subject. He found “enormous similarities between Britain and America,” he recalled, recently. “Crazy police driving, serious injuries, deaths – and very little interest around the departments in exploring this further. It was seen as the natural thing, same as in the States. Bad guy runs, cop chases.” A sharp spike in fatalities at the end of the 1990s did lead to the IOPC (then under a different name; it has transitioned through several rebrands) bringing in a criminologist, David Best, to investigate accidents resulting from chases. Best came to the conclusion that standards varied wildly from district to district and that, in the main, officers were given a lot of leeway once the sirens were on and the suspects in flight. There seemed to be a received locker-room understanding: most chases turned out fine. “We’ve done a lot of work on this in America,” Alpert said, “where an amazing number of officers don’t wear a seatbelt. It’s called ‘phantom ninja’ [syndrome]. You’re inside the car with lights and sirens blaring and you think you’re immune and nothing bad can happen. But it can. It does.”

Likely everyone can agree that in extreme cases – terrorists at large, a killer on the run – pursuit will be justified. Criminologists such as Alpert and Best worry about the million more ambiguous scenarios: those chases of less certain aim, where risk and reward, responsibility and culpability are likely to get confused. Embedded with the police-complaints office in the early 2000s, Best became uneasy because, as far as he could tell from his studies, only about 5% of police pursuits that ended in fatal collisions involved “someone the public would regard as a serious criminal”.

Facebook Twitter Pinterest Matthew Seddon. Photograph: INS News

“Mostly these were people with mental health issues,” Best said, “or people who distrusted authority, often young people, vulnerable people, the diminished or dispossessed. People who might have done something wrong, but not in proportion to the chase.” Alpert said: “That’s the other myth, the ‘dead-body-in-the-trunk’ assumption – this idea that if you flee you’ve done something really wrong. The truth is that it’s often young males who’ve done a few small things wrong, missed warrants, not shown up in court. And bad choices have a way of piling up.”

Turning it over in her head after the Reading accident, Bryony wondered why her boyfriend had fled in the first place. She knew Matthew had come in to bad habits, buying and reselling his secondhand cars. He would drive them around Reading without insurance, insisting that the occasional fine worked out cheaper. That night, Matthew only had a provisional licence and ought not have been driving alone. A toxicology report later found that he had traces of cocaine in his body. (It was made clear at a later hearing that these traces, hours old, would not have impacted his driving or his decision-making.) Around a year earlier, his brother, Sean, told me, Matthew had served some weeks in prison. Out on the Reading bypass, he didn’t have a seatbelt on when he crashed. But then, neither did he have a dead body in the trunk.

Bryony only wished she had been with him. She was convinced Matthew wouldn’t have run if she had been there in the Fiesta. The couple had barely started trying when they learned Bryony was pregnant. That tester kit hidden in her bedroom was a positive one. Their daughter was born six months after the chase that killed her father.

Within hours of the Reading crash, Thames Valley police referred itself to the IOPC, which started an independent investigation. Statements were taken, dashcam and CCTV footage downloaded. A case worker set out to visit Matthew’s mother, Julie Seddon, at her home in Suffolk. Born and raised a Mancunian, with a warm, smile-first manner allied to blistering frankness, Julie had been telephoned on the night of Matthew’s crash by her other son, Sean. He told her to make a cup of tea and sit down; and after that, Julie said, she could not stand up again for hours. “It’s a ringing in your ears. In your brain. Like if you’ve lost sight of them in the supermarket and you panic, that you’ve lost your child, it’s that feeling. And it never goes.”

The IOPC case worker eventually showed Julie footage from the Reading road. She wasn’t shown Matthew’s actual crash, but she did see images of the pursuit that preceded it. There was a lot of video available, taken from multiple cameras around the city, making Julie wonder, later, why officers didn’t “back off, let him slow down, note down the car registration – get him another day”.

When I asked an experienced officer from another district to explain how difficult it was to track someone who had won clear in a chase, the answer came with a cool shrug. Not very difficult. “There’s always other options,” he said. Interviewing. Intel. Close scrutiny of CCTV. On his computer, he showed me how they tracked down one chase suspect who had ditched his stolen scooter, jogged a few blind corners and then removed his helmet, clearly revealing his face, all shown in CCTV images so numerous they ran together as if in a children’s flick-book. “We’ll get you,” the officer said.

Julie noticed something else in the footage from the Reading bypass that troubled her. She could see Matthew’s Fiesta in flight and police cars coming after him at a distance. But wasn’t that another police car out ahead of the Fiesta as well? She peered closer. The forward police car was halted in the dual carriageway, taking up one of the two lanes. As an expert witness would later confirm, this was the roadblock that had caused Matthew to veer and lose control. Was this normal for a chase, Julie wanted to know?

A chase is a heightened, erratic thing, freighted with unpredictables and hard-to-account-fors. It may be that there is no normal police chase, in the way that there is no normal barfight. National guidelines have twice been refined, in 2004 and again in 2011, to help police forces reduce the risks. Since 2014, there have been efforts to school police drivers in the use of simple terms to describe the levels of risk in any given chase. A thick chapter in the policing manual reminds officers to assess and reassess. Ask: are the dangers of continuing this outweighing the reasons for starting it? Would a later, calmer, walking-paced investigation be better?

Facebook Twitter Pinterest A Sussex police car damaged after a collision with another vehicle during a pursuit. Photograph: Marc Macdonald/Alamy

A police driver’s competency is meant to dictate the top speed at which they may chase a suspect, so that “advanced” drivers (two months’ instruction) can go faster than “response” drivers (one month’s instruction), who can go faster than greener “basic” drivers. Rarer, because of the costs of training them, are “tactical” drivers, who are qualified to box in a suspect, ram them and pursue in packs. But any chasing police driver must constantly radio back to a control room, describing circumstantial detail from the road and other possible risk factors – and await permission to keep on. If control says stop, the driver must stop. Control depends, almost entirely, on a driver’s accurate verbal description of a chase in order to make this decision.

The veteran London lawyer Andre Clovis, who has worked on a number of cases of pursuits gone wrong, told me: “Two tendencies crop up time and time again. Officers engaging in pursuits when they’re not qualified to do so. Or, when they are qualified, you see them fail to seek the appropriate authority from control.” Clovis, moustached, with square spectacles, handled his first botched chase two decades ago. Now in his 50s, he was weary of waiting for sensible reform. “Terrorism, violent crime, I understand – you pursue. I don’t say never, never pursue. I just say it has to be proportionate.”

In 2013, Clovis represented a young Polish family who had been involved in an accident in south London. Maciek Was was driving with his wife and two children one day that January when a chase came up behind them: a wanted suspect in flight with a police vehicle behind. The wanted man collided, hard, with the back of the Was family car. Maciek’s 13-year-old daughter, Wiktoria, was killed in her seat. “The guy they were chasing that day,” Clovis said, “he was an inconvenience, yes, he was a pain, a particular problem at that time. But not a suspected murderer, or rapist, or paedophile, or terrorist, someone who, if the police didn’t get now, they might never.” Clovis worried that officers, mid-chase, too often got lost in the moment. Discussing the Wiktoria Was case, Clovis kept circling back to a detail that haunted him: how, after the crash, a smashed and dazed family – one of them dying – were ignored while this police chase continued on foot.

After a formal coroner’s inquest into Wiktoria’s death in summer 2015, a south London coroner, Tony Badenoch QC, was so alarmed by aspects of the accident that he wrote to the commissioner of the Metropolitan police. A long, honest letter came in reply, in which the Met pointed out that the officers involved had been cleared of any criminal or disciplinary offences; but that steps were being taken to help officers improve their decision-making in a crisis. This would not be easy work.

“Suitable training can attempt to mitigate but not entirely eliminate the effects of [a] basic element of human nature,” the Met’s letter stated. “That human decision-making under conditions of threat, risk or stress … is not purely an intellectual exercise.” There was a tendency to “fix” on a target, for instance, which could mean a narrowing of attention. Loss of hearing. Tunnel vision. Officers in a chase could succumb to something called “red mist”, a psychological condition that was described in the letter as a sudden collapse in judgment brought about by high-risk scenarios. At a recent inquest, a police inspector with rich experience of pursuits was asked if “red mist” had always been a problem. The inspector, Richard Auty, replied: “It’s humans, that’s the problem. The person driving the [police] vehicle is human and they have emotions … This is not something that’s ever going to go away.”

There are times it is unequivocal, glaring: we must chase. Late one night in October 2017, on west-London roads around Maida Vale, there was a horror spree: two 18-year-olds riding a motor-powered scooter and robbing pedestrians at knifepoint, at random. Several times they stabbed people even after they had taken their possessions. One man was stabbed and killed for his iPhone. The spree went on and on, and a police chase – the model chase, all things considered – brought it to an end. The perpetrators were pursued by Met officers who, as radio transmissions made clear, carefully weighed the risks involved with their control-room superiors. Driver: “Risk medium, wrong side of the road, nothing towards, speed still four-zero [40mph].” Control: “This pursuit is authorised, we believe this vehicle possibly involved in the stabbing.” The two 18-year-olds were caught.

A few months later, I drove the same west-London roads with two trained pursuit drivers from the district. Career-long chasers, Matt Carey and Alex Phillips had miles and miles of the criss-crossed city under their belts. Phillips was nicknamed “Robocop” by Carey, for his quick-twitch reactions and the way he piloted their unmarked car with a grace that bordered on the athletic. Reasonable, intelligent, these were just the sort of officers you would want to show up in a crisis. (Just the sort you would rope in to chaperone a visiting reporter, too.) Carey and Phillips told me they knew in their bones, the same way they knew a million things about the various and near-impossible job of street policing, from hard-won situational experience: that some people needed going after. The Police Federation of England and Wales, the closest thing to an officers’ union and an influential voice in matters of domestic justice, has made plain its view that to curb police chases would be to curb good policing.

Carey and Phillips drove me through Paddington, then north into Maida Vale. On a roundabout, Carey recognised a driver in a van and, briefly, we went after it. Phillips pushed up his armrest to press a concealed button and our blue lights flared. Cars in front parted like startled fish, but the excitement came to nothing, and soon we parked up to buy sandwiches for lunch. It was sunny, leafy, apparently benign in Maida Vale that day. The two 18-year-olds who had robbed and killed here were shortly to be tried at the Old Bailey. (They were found guilty of murder and sentenced to life.) While we ate our sandwiches, Carey said that a chase wasn’t always the answer. But it was an answer. If it came to that, he added, “all I can say is our guys do their best”.

When Julie Seddon received the report into her son’s death from the IOPC, in summer 2014, a year-and-a-half after the accident, she was bewildered. It was not clear to her whether Thames Valley officers were being held responsible for what happened that night or not.

Who owns a chase, ultimately? Who is most responsible, pursuer or pursued? Since coming into effect in the early 2000s, the Human Rights Act had made explicit a duty on officers to take positive action to protect a citizen’s right to life. But how did this apply when the officer and the citizen were locked in a race at 80mph or upwards? Could it still apply? There had never been a trial come to a British or European court that asked these questions. Who owns a chase? In 2014, when Julie received the report into Matthew’s death, nobody could say for sure.

Julie had other concerns when she read through the 90-page document. Some of the remarks provided by Thames Valley police officers who were present on the night of the crash astonished her. “I can’t remember … No idea … I’m not answering that one.” One exchange went:

IOPC investigator: “Are you allowed to initiate a pursuit?” Thames Valley officer: “I cannot remember.” Investigator: “You can’t remember what you’re entitled to do, every day that you go out? … I find that difficult to understand, why five minutes into an interview you just can’t remember what you’re entitled to do on the street.” Officer: “I’m not sure. I can’t explain.”

The report concluded, with bald dismay, that individual Thames Valley officers had “withheld accounts and attempted to frustrate the investigation”. At one point, the officer who first chased Matthew was asked about some of the wilder manoeuvres during those 4 min 22 sec. Roads taken the wrong way. A near thing between two police cars at a junction. Why was none of this detail radioed back to control, IOPC investigators wanted to know? “Are you not providing this information to the control room because you don’t want the pursuit terminated?” The officer was silent. He wasn’t answering that one.

Facebook Twitter Pinterest Julie Seddon at the 2015 inquest into her son’s death. Photograph: Kerry Davies/INS News

Dissatisfied by the report, Julie hoped for firmer answers when it came time for a coroner’s inquest. That took place in autumn 2015, two-and-a-half years after the accident. By this time, Bryony and Matthew’s daughter was walking.

What happens when someone you love dies in a police chase? When the ones who have to identify a cause may be the cause? You enter a sort of limbo between different blocks of the British justice system, and the schedule for answers, here, is glacial. First comes the IOPC investigation (six to 18 months). Based on the evidence the IOPC gathers, there may be referrals to the Crown Prosecution Service, for the CPS to consider criminal charges (another year). It is very uncommon for an officer to be prosecuted after a chase gone wrong, as the IOPC acknowledged formally in a report last year. Nonetheless, relatives might lodge an appeal with the CPS against a negative decision (another six months). Meanwhile, the coroner’s inquest gets pushed back while the appeal process grinds on. Not infrequently, families sit down at inquests having already come out the other side of their grief.

Coroner’s inquests are meant to be inquisitorial not adversarial events, designed to provide answers and relief, not to establish legal or criminal blame. At Matthew’s inquest, everyone from Julie to the chief constable to the control-room operator arrived with lawyers. There was a testy back-and-forth between barristers on the first morning about whether Julie might put a photo of Matthew in front of her. “It was really hotly fought, adversarial throughout,” said Kirsten Sjøvoll, the barrister who acted for the Seddon side. Young, understated and direct, Sjøvoll had never handled a pursuit case before. For three weeks in Reading town hall, she sparred with Thames Valley’s barristers, inching through a volley of objections to put before the coroner some facts she believed significant. The officer who initiated and led the Reading chase was not qualified to go at such high speeds. Under questioning from Sjøvoll, the control-room officer agreed that he had not been given all the details of the chase. Had he known more, he acknowledged, he would have ordered a halt.

After the inquest, Sjøvoll and a solicitor working on the case, Beverley McBean, told Julie that she had strong grounds for a financial claim against Thames Valley police. If Julie was to pursue this, she would need to have the stamina for more waiting, more fighting. There would be a trial. They would need to hire a QC, as some of the arguments Sjøvoll and McBean hoped to make involved human rights, arguments that had not been tested in front of a judge before. Did Julie want to carry on?

Lawyers in the field will tell you that this moment after the coroner’s inquest, two or three years on from a death, can be the most deflating for families. Hours of cross words and crossed swords, a feeling, almost, that they as the relatives were on trial, and in the end no emphatic outcome, nobody blamed or exculpated. After the death of their daughter Wiktoria, Maciek Was and his wife chose not to pursue a further claim against the Metropolitan police. Too broken, too beaten up, Maciek told me. “It’s talking, and talking, and talking,” he said, “and this is extremely painful.”

Understandable as it is, any time a bruised and exhausted family gives up their claim, it undercuts momentum for reform. Back in the 2000s, the academic David Best had titled one of his reports, with acid bluntness, Why Are There No Lessons Learned from Road Traffic Incidents Involving the Police? A veteran lawyer like Andre Clovis would answer that it is because hardly anyone insists. Tony Badenoch, the coroner who led the inquest into Wiktoria’s death, and who wrote to the Met in the summer of 2015, had been concerned at the time that lessons about police chases were not being learned. “There is a risk that future deaths will occur,” Badenoch warned, “unless action is taken.” The fear was that another child might die, needlessly. It took about a year.

On a Wednesday afternoon in 2016, Martin Cooper and his wife, Diana, were looking after their four grandchildren in Penge in south London. It was the last week of the school summer holiday. Martin’s daughter, Rozanne, was there too. “There was a park down the road that had swings, climbing things,” Martin said later, sitting in his solicitor’s office, recounting what happened that afternoon. “We decided we’d have a trundle down with the kids, maybe get an ice-cream, something to break up the day. And that’s what we were doing at the time. Just walking down the road.”

The Coopers were on the pavement, standing a little apart, when a chase came up on them: a stolen Ford Focus in front, a police car behind. According to bystander testimony, the two vehicles were about a car’s length apart and moving at about 50mph. A witness on the Penge road remembered thinking that “if I recognised this was dangerous, why didn’t the police?” Martin said: “We heard the siren and we stopped. The pursuit came directly towards us.”

Retired, in his 60s, Martin likes to wear bright colours and glasses with clear frames. His grey hair was combed back in tufts: a cool grandpa. Whenever Martin stopped talking to cry, his wife Diana, who was quieter, touched his arm. He said: “The cars swerved round and that next moment in time, well, I don’t know what. I don’t know what. Because it’s beyond belief what you’re seeing. Because it’s not something you could ever imagine.”

The stolen Ford crashed into a bollard, rose up and came down on five members of the Cooper family. Martin’s daughter Rozanne was killed. Three of his granddaughters were injured, one so seriously that she spent a month in hospital. A grandson, Makayah, died under the car with Rozanne. Makayah was 10. “This is a silly thing,” Martin said, “and this is about my upbringing, this is a really silly thing. But as soon as that happened, when the driver’s door flew open, and the driver went off running, that was one of the most hurtful things for me. To think that someone could do that and run away. Not stop. Not help.”

Facebook Twitter Pinterest Rozanne Cooper and Makayah McDermott, who were killed by a car being pursued by police in a high-speed chase in Penge, south London. Photograph: Facebook

The driver of the stolen Ford, Joshua Dobby, was caught. Afterwards it emerged that Dobby had been involved in another police chase days before – this one de-authorised by the control-room after four minutes of traffic-scattering chaos, “due to the very high level of risk created by the offender’s driving”. The second, fatal chase that came up the Coopers’ road was not stopped by control. It had lasted for six minutes, one-way roads taken in the wrong direction, a red light skipped, a parked vehicle clipped, a pedestrian narrowly missed. Several times, the police driver described the risk to his control room as low.

Sat in his solicitor’s office, bowing his head, Martin said: “I expect you’ve heard lots of people tell you: ‘They’re only doing their jobs. What are the police supposed to do? Let these people get away all the time?’ And I suppose we, naively, went down that route of thinking at first. It’s a generational thing. You believe the police have a job to do. Let them do it.” Only later did Martin have doubts. “Ten or 12 years old, that stolen car,” he said quietly. “You’d never sell it, it would’ve had scrap value of about £100. You want to chase that? Blue lights, sirens – for £100? … Dobby is to blame,” Martin said. “But I know that if at some point those police officers said enough’s enough, my daughter and grandson would be alive.”

On the day I met Martin and Diana in their solicitor’s office, a full IOPC report into the deaths of Rozanne and Makayah had just been delivered. It was sitting on the table of the conference room, there for the Coopers to take home and read. They weren’t ready to tackle it yet. Instead, we fell to discussing police chases in general. Martin said: “If you look at the worst possible outcome, our outcome, there would be no pursuits. Because the worst can happen. We’re sitting here. It can happen.” He was thinking aloud, not offering a serious proposal. I told Martin that it had been tried before, both in the UK and abroad: not chasing.

Humberside police suspended high-speed pursuits in 2003 over safety fears, but reversed the decision 18 months later. (When I contacted Humberside’s then-chief to ask about this, he did not wish to comment.) US cities including Milwaukee and Kansas City have flip-flopped likewise, abandoning and then reinstating the chase. In Detroit, in 2017, a teenager’s death and a subsequent civil lawsuit brought about an end to officers speeding after drivers breaking the speed limit.

“It’s a myth that if you quit chasing, everyone’s going to run,” Geoffrey Alpert, the criminologist, insisted. He pointed to successes in districts of Florida and Baltimore where police were only authorised to chase violent criminals. David Best said that during his time embedded with the police complaints office he found “no evidence to support the idea that if you stop chasing, crime goes up”.

Chase lots, or chase little. What mattered most, said Martin Cooper’s solicitor, Michael Oswald, was that police drivers were not only taught but incentivised to keep their heads. The report into the deaths of Rozanne and Makayah, sitting on the conference-room table in front of us, included findings by the IOPC “that two officers may have committed criminal offences both during and following the pursuit”. Martin and his family had been confused, then, to receive a letter from the CPS, agreeing that, yes, there were evidentiary grounds to bring charges against the officers; but there would be no such charges – “not in the public interest”. The phrase jarred with Diana. For the first time, sitting in the conference room, she spoke up, asking softly: “What are we?”

The Coopers were readying to leave when Martin seemed to flinch, and he turned to his solicitor, saying: “One of my questions I was going to ask, Michael, before we go – ” But the stricken grandfather’s voice failed him and he had to take a moment. Diana put a hand on his arm. “We’ve lost Rozanne and Makayah,” Martin said, eventually. “But will there be anything to come out of this? Anything to help other people, I mean.”

Oswald paused. Earlier, he had confessed to me his admiration for embattled relatives such as Julie Seddon, those who were left for years with unanswered questions, who had come to understand the police complaints process was flawed, but engaged with it anyway. “I’m not here to defend the system,” Oswald told the Coopers. “I’m here to represent you through it, and through all of its faults. But this experience that you’re having – 20 years ago, families in your position would have been having an even worse time. And the reason that your experience is slightly better is because those families engaged. They pushed. They fought.”

Oswald and the Cooper family agreed they would challenge the CPS’s decision that it was not in the public interest to prosecute. “The public interest is about having safe streets,” Oswald said. “And that can mean being safe from criminals, which might require the police to drive dangerously sometimes. But there is also quite a straightforward public interest in having police behave properly. Recognising that we ask them to do a difficult and dangerous job and giving them the leeway to do that, yes. But then, when they step outside that leeway, holding them to account.”

The Thames Valley officer who started the Matthew Seddon chase, and who kept on it till the end, said several times while under investigation: “I believe it’s what the public would have wanted me to do.” A spokesperson for the College of Policing, which helps train officers to chase, said: “The public expect their police service to catch criminals.” We want the chase – or that is what police have come to understand. After a novel form of street crime began to cause panic in 2016, the public declared this interest more explicitly.

People started robbing pedestrians, sometimes violently, while riding past on high-powered scooters or mopeds. The statistical centre of the maelstrom happened to be my neighbourhood of Camden in north London, and a road I walked twice a day was one of the worst-hit by scooter crime in the country. Everyone I knew also knew someone who had been holding a phone or a bag only to then watch it hum away, lost, on a 125cc scooter.

Competing theories were put about as to the root causes of this kind of scooter crime: the home-delivery boom had put more scooters on the streets to be stolen and used in these sprees; this was an Instagram-age crime, inventive and visual and easily copied; or maybe it was all a form of exotic protest, an effort to taunt and embarrass London police after the chase death, in 2014, of a young rider called Henry Hicks. Where there seemed to be fuller agreement, in local papers and in local pubs, was on the matter of a response. Even liberals clenched their fists: the police had to do more to get after these young thieves.

Earlier this year, I interviewed two of these thieves, both of them under 18, both speaking to me on the condition of anonymity. I was struck more than anything by their bravado, their absolute certainty that they would not be caught. The boys found the work lucrative, they said (“In one day you can make £800”), and easy. You snapped the steering lock on a parked moped and rode it around in pairs, one driving, one snatching. You stripped the vehicle, pooled what you had stolen, advertised it online. Both of the young men felt confident enough to put their wares up for sale on Instagram. If they got into a chase – if the one driving felt the double tap on his helmet that meant “police, behind” – they felt they only had to drive long enough, cannily enough, perhaps desperately enough to win out. “You need to be ready to do anything to get away.”

The scooter versus the police car, then, was about as volatile a chase as had ever been seen. Clearly the police needed new tactics, new thinking. On the day I shadowed Matt Carey and Alex Phillips on their west-London beat, many of their colleagues were away being trained in the use of something called a DNA spray, a substance that could be squirted at a passing suspects and used to identify them later. There was talk of raising kerbs, or installing strategic “street furniture” to stop riders mounting the pavements to escape. Carey, ever reasonable, believed that scooter crime would be greatly reduced if only more drivers properly secured their vehicles. (No stolen scooters, no scooter-enabled crime.) Pedestrians might also spend a bit less time flaunting £500 smartphones. But Carey was a realist. He seemed to know that a message of “look after your stuff better” was not the punchy, assertive thing to placate those citizens who believed they were living through an unstoppable crime epidemic.

Scooter crime “is one of the hardest crimes I’ve had to deal with”, Carey said that day. I asked him whether the fact of the riders being mostly teenagers made the decision to chase them more difficult. Carey answered: “Course it does. But that’s what we’re here to deal with.” He meant: the difficult. “If we don’t deal with it, nobody does.”

A grim apex was hit in Camden in summer 2017, where more than 1,300 scooter-enabled crimes took place inside a month. Camden’s superintendent spoke to a local newspaper, hinting at bold new tactics, under wraps for now, soon to be introduced. By 2018, the secret was out. All over London, trained pursuit drivers had been authorised to go after suspects on scooters and, when close enough, initiate “tactical contact”. Put less coyly, the police would ram the bikes, knocking their riders off.

A moped stopped by a police vehicle following a pursuit in 2018. Photograph: Metropolitan Police/PA

A controversial tactic, it would be used 60 times in the UK in 2018, according to IOPC figures. And scooter-enabled crime did fall. At a community meeting in my neighbourhood, an inspector stood up to say the numbers had been halved: “On this occasion we can take credit. We’ve been knocking people off their bikes. And everybody loves it when we see a moped on the floor and someone in cuffs.” Earlier, at the same meeting, the inspector’s colleague had described the core offenders as “young, almost exclusively under the age of 18, some as young as 12”. I thought: and everybody loves this?

The public had clarified an interest – they wanted the scooter kids stopped – and the police had answered. The method did not sit well with everybody. Diane Abbott, the Labour frontbencher, pointed out that if a civilian used their car as a weapon, they would be arrested and charged. “Police are not above the law,” Abbott wrote on Twitter. Sajid Javid, the home secretary, then new in post but quick to relish such sheriff-in-town pronouncements, wrote back: “Criminals are not above the law.”

Around this time, I met an off-duty coroner who, discussing the new ramming tactic, raised an eyebrow and asked: why not swear the police in as judge and jury too? “It’s wild west stuff.” Because what if a suspect was thrown off their bike (injured, killed) and later found to be innocent? This happened at least once, to another client of the Cooper family’s solicitor Michael Oswald. The client was under 18. The city did not tend to look fondly on young men on scooters just then. But he was guilty of no criminal offence when, riding around on a London A-road, he was rammed off his bike by a police officer. A barrister called Michael Etienne, a colleague of Oswald’s and a fellow member of an organisation called the Police Action Lawyers Group, told me he is profoundly uneasy about the changing flavour of policing. Etienne acknowledged that running thieves off their scooters probably was effective as a crime suppressor. “But so would be cutting off their hands.”

The introduction of the new ramming tactic came along at a time when, on a higher legislative level, there were serious moves underway to relax accountability laws. A proposal from the Tory government was circulated in summer 2018, suggesting serious legal changes that would downgrade police accountability after a chase gone wrong – to make clear, the proposal said, “that it is, in general, not in the interest of the general public to hold a police officer liable for the standard of driving of a suspected criminal”. The document made clear the legal changes were being proposed, in part, because of pressure from the Police Federation. (When I approached the federation for comment, it declined.) Speaking at a Police Fed conference last year, Sajid Javid said he would back the proposed changes, “to protect the protectors”.

Lawyers pooled their concerns about this proposal and drafted a joint statement in response. They referenced the disaster that had befallen the Cooper family, warning that to legally relax the accountability of officers in chases would be “dangerous and misconceived” – hardly in the public interest. They quoted at length from the Human Rights Act, the parts about the obligation on state agents to be proportionate, measured, and to take active steps to safeguard citizens’ lives.

Quoting was about as much as they could do. There had still not been a legal case that tested the Human Rights Act in the context of a police chase. If a suspect was pursued too hard, too fast, too long, could that even be a breach of their right to life? Julie Seddon and Bryony Morgan were about to be the first to try to argue this in court.

Half a decade had passed since the Reading crash. Matthew Seddon’s daughter was five years old, quiet and shy like her mum, with a coy smile that burst through, people said, like her dad’s. Bryony had moved on since the accident, but at the same time she had not. Matthew’s name was tattooed prominently on the underside of her arm. She had continued to live in the same part of Reading, always in places close to the crash site. “I don’t know why.” Whenever she talked about what happened, she leaked tears. Julie told me: “She’s mourning what she never had.”

After the inquest, Julie had been seized by long bouts of energy, and had enrolled at a Suffolk college, completing courses in maths and accountancy. By renewing applications for legal aid, she was able to keep instructing her solicitor, Beverley McBean, and her barrister, Kirsten Sjøvoll. Later, when a trial date was set, they hired a QC, Heather Williams. Thames Valley’s lawyers brought in a QC too. The two sides faced off in front of a judge at Central London county court in October 2018.

For two days, focus was trained microscopically on the four-and-a-half minutes of the Reading chase. There was no danger posed by Matthew’s driving before a police car pulled up behind him, the Seddon side argued. But he initiated the chase by speeding off, the police side countered, and it was the manner of his driving then that made him vulnerable. The Seddon side said this vulnerability was under the police’s control, because they could have stopped the chase at any time. So could Matthew, came the reply. The Thames Valley side said the police had met any obligation to Matthew by having in place procedures to regulate its pursuits, and beyond that … Here the judge intervened. Wasn’t the whole point, she asked, “that you did have procedures in place, but you didn’t comply with them?”

Facebook Twitter Pinterest The scene of the chase and crash that killed Matthew Seddon in Reading in 2013. Photograph: INS News Agency Ltd

One by one, officers from the night were sworn in as witnesses. Julie listened to their testimonies with mixed emotions. Questioned individually, she could see that these were people as well as police officers, and she was struck by how different they were. There was the officer who went after Matthew first and who didn’t keep his control room fully informed during the chase itself. Julie felt he seemed unrepentant in the witness box, and she later confessed she had the profound urge to punch him. Then there was the officer she found absurd when he explained why he parked his police car out in front of a chase instead of pulling over to the side. (The officer, deviating from earlier statements, said he was worried about “bouncing back” off the bypass kerb.)

Julie had come to see that the control-room officer, not given the full picture by his colleagues on the road, had been sorely limited in his ability to do a proper job. And she pitied the final pursuit driver, late to a chase that ought not have carried on so long, finally running over Matthew’s body. In reporting this story, I was unable to find a police driver willing to describe to me what it was like being part of a chase gone wrong. Thames Valley police declined a request to let me interview its officers. I did find a statement buried in Julie’s IOPC report, describing the seconds after the crash, when the pursuit driver who had struck the body in the road was left pale, hyperventilating, repeating to colleagues: “Mate … I hit him, I ran over him … But mate, mate … ”

“I feel sorry for him,” Julie said.

After all the evidence and arguments were heard, the judge retired to weigh her verdict. She would need to make a three-part determination. Were the Thames Valley officers, caught up in something fast and unpredictable, still duty-bound to take steps to protect Matthew’s life as outlined in the Human Rights Act? If so, was this duty breached? And if so, was there a real prospect that Matthew would have survived if such a breach of duty had not occurred?

In late November, the judge sent her decision to both sides. Despite Matthew’s undeniable agency in the chaos of the night, a duty of care to him had been breached – the moment the chase became dangerous and disproportionate and was carried on anyway. “The claim succeeds,” she wrote. At Beverley McBean’s office, they gasped. Kirsten Sjøvoll felt only relief. Julie was back in Suffolk when the lawyers called her. They told her to sit down.

The inquest into the deaths of Martin Cooper’s daughter Rozanne and grandson Makayah opened at Croydon coroner’s court about a month ago, at the start of June. After a 15-day hearing, the jury returned a finding that was critical of the police driver’s risk-reporting and the lack of appropriate supervision from control. Jury members questioned whether the pursuit should have started at all, and wrote that it “should not have continued throughout because the seriousness of the crime was relatively low compared to the ongoing risk to the public”. The Met said in a statement it would “take time to fully consider the jury’s comments ... [We] learn from each tragic case.” A spokesperson added that the driver involved would face an internal misconduct hearing “in due course”. The Cooper family learned, separately, that their appeal to the CPS for external criminal charges to be considered again had been refused.

In a little under three years since Rozanne and Makayah were killed, another 45 people died during police chases in England and Wales – 10 of whom were chance bystanders. They included a student in Leicester, an elderly couple in south London and an off-duty community support officer in the Midlands. Last November another child died – a one-year-old boy. In April, a 74-year-old pensioner died, struck by a fleeing vehicle while crossing the road in King’s Cross in London. In May, those proposed changes to UK law, protecting officers from lengthy investigation after chases gone wrong, were approved by the Home Office. “We’ve got their back,” Sajid Javid said in a tweet.

As a result of the Matthew Seddon verdict, Thames Valley police told me it had “reviewed a number of our policies and our training and improved the way we respond to incidents”. The police force brought misconduct proceedings against five of its officers involved in the Seddon chase, clearing three. One was given management advice. Another was found to have breached the standards of duties and responsibilities, but received no sanction.

After the judge found in their favour, Julie and Bryony were awarded nominal damages from the police – four-figure sums, adjusted downwards to account for Matthew’s role in the chase. Julie received the most, £4,800. A few weeks after the trial, I asked her if the money had made any difference. An eyebrow went up. “This was never about money,” she said. Julie and Bryony had been criticised for bringing their claim, obliquely by the local press, overtly by strangers on the internet. Untypically, Bryony had pushed through her shyness to engage with Facebook commenters. She wrote of Matthew, to those “saying they are glad he’s dead etc … he was not a thief, he was not a big-time criminal, he was a scared young boy.”

When we met this year, in a restaurant in Reading, I asked Bryony if she truly believed this. It was snowing outside and she spent long minutes staring out into the weather, composing herself before answering. She could see now, she said, what children she and Matthew were in 2013. “Like, we hid the pregnancy test under a pillow. In my mum’s flat. And we didn’t think anyone would find out.”

Using documents from the trial, I had been able to figure out the precise route Matthew drove around Reading on the night he died. A video reconstruction of his journey had also been shown to the judge in court. Inexplicably, minutes in, driving wildly on a trajectory out of Reading, Matthew suddenly turned full circle and headed back the way he had come. As a strategy for evading capture, this made no sense, and I asked Bryony if she had come to the same conclusion others had. That Matthew, in deep, had turned around to go back towards their tower block. She looked out of the restaurant window. “That makes it worse,” she said, “if he only wanted to come home.”

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• This article was amended on 2 July 2019 because the inquest into Matthew Seddon’s death took place at Reading town hall, not Reading crown court as an earlier version said.