How safe can we be? On the night of the Paris atrocity I was out with the Bedfordshire police, watching what they do and what they can no longer do. Blue lights flashing, dashing through the streets of Luton and Bedford in the patrol car, I talked about cuts with Olly Martins, the police and crime commissioner. As we spoke about the local Islamist terror threat we couldn’t know how much closer it was coming.

Commissioners and chief constables are kicking off up and down the country, from London’s Met to Liverpool, with unprecedented protest at the 25% of cuts they have suffered and worse to come in next week’s spending review. As France’s president, François Hollande, announces he is boosting its police force by 5,000, Britain is scaling back. Nationally, 17,000 police officers have gone, with another 22,000 to go this time: neighbourhood police no longer pound the streets in many areas.

At first glance, the police case looks weaker than other public services waving shrouds to ward off calamitous cuts: NHS, social care, child protection, benefits, the arts, housing, science or further education all dread what’s coming. Crime has fallen since the mid-1990s right across the west: it fell 8% in Britain again last year. But that ignores soaring cyberfraud and much else. So let’s look at what the police actually do.

That night, a man was reported going into a wood with a rope, threatening suicide. Two cars dashed to the scene, officers searched through the trees, joined soon by an ambulance and a police helicopter with heat-seeking equipment. Over the radio we heard them find him, guiding those on the ground to the tree – dead or alive, no one knew. The man sat on a branch but wouldn’t budge, so the fire brigade came with a ladder and down he came. Was that a good use of funds – for lack of adequate mental health services?

Around four possible suicides are reported a night here. Some are frivolous, such as the boy later found larking about in a nightclub after being thought missing for seven hours. But all are taken deadly seriously. “Oscar One”, who’s been a control room officer for 15 years, makes the life and death decisions: early that night he already had 18 calls he reckoned needed attending, with only 11 officers to send.

Mental health problems dominate, making up to 60% of those taken into custody. Everyone I spoke to that Friday complained bitterly that social workers and mental health staff went off duty and handed their problems to the police. Listen to the control room and you get the picture: there’s not much crime, but torrents of emotion and distress. A missing teenager refusing to come home is said to be hiding in a McDonald’s. Sure enough, switching on the relevant CCTV, there she is. The more other services are cut, the heavier the burden that falls on the police. “We scrape up,” said one brutally. “There’s no one else.” But crime stats ignore all this.

‘After Paris, would you want to be the home secretary who said getting down the deficit was a matter of ‘national security’ while cutting the safety net of a neighbourhood police force?’ Photograph: Charles Platiau/Reuters

Funded as a rural force, Luton amounts to a north London borough: deprived, high youth unemployment, third highest for gun and knife crime, yet one of the poorest funded. Islamicist radicalisation is a constant threat: a large family vanished to Syria from here. Britain First far-rightists provoke with anti-Muslim demonstrations, invading mosques to hand out bibles.

The threatened 29% cut will deprive the 1,074-strong force of 300 officers. Martins tried to raise the police precept by 15%, or just 38p a week, but the government forced a local referendum with a question that misled voters to think their whole council tax would rise 15%, so it was lost. He threatened zero tolerance speed-enforcement cameras on his stretch of the M1, collecting £35 each from drivers’ awareness courses. That caused an outcry from the transport secretary and the tabloids – and the Alliance of British Drivers called it “utterly obnoxious”. He suggested commercial logos on his cars and uniforms – a sensational distress flare.

The question home secretary Theresa May has to answer is this: what should the police stop doing? They might stop chasing might-be suicides, or no longer guard psychotics the hospital won’t restrain until psychiatrists section them. A return to earlier drinking hours would save police keeping the peace until 5am outside pubs and clubs. We had a call about a man lying in the middle of the road, his eyes rolling – but when we got there he’d gone off with his friends, drunk. There’s little time now for spot checks on suspect cars, which used to lead to 60 arrests a month. Just one officer visits all the county’s schools, even though gangs are a serious problem. Someone calls to report drug dealing, but police can’t follow that up.

What worries them most is no longer patrolling neighbourhoods as they did, listening and earning local trust. In the past, a neighbourhood tip-off from a local Muslim led them to a machete-wielding convert from Jehovah’s Witnesses to Islamicism – building up these kind of contacts takes time they’re unlikely to have in the future. Labour’s police spokesman, Jack Dromey, echoes officers when he says “neighbourhood policing is the eyes and ears of counter-terrorism, key to the detection of those who would mount attacks on our citizens and our country, now being arrested at the rate of one day. Paris is a tragic warning”. David Cameron has announced 1,900 new intelligence staff, yet he cuts the police with on-the-ground knowledge.

Astonishingly, he has just written to his own Thames Valley chief constable complaining about cuts in Witney, displaying the same breathtaking ignorance about the real-life effect of his cuts as when he complained to his council leader. Expressing his “disappointment”, he complains of the closure of seven police stations and cuts in hours at others. Couldn’t their £57m cut be achieved with “back-office efficiencies and joint working”? Labour called it “jaw-dropping hypocrisy”.

You could give more to mental health and social services to ease their case loads and save police time. Vanished youth services could be restored, instead of police coping with the fallout. If not, then we need the police to sweep up after the cuts in every other service.

After Paris, would you want to be the home secretary or the chancellor who said getting down the deficit was a matter of “national security” while cutting the safety net of a reassuring, neighbourhood police force that makes people feel secure in a time of fear? There comes a tipping point where crime and disorder will rise: we may be about to find out exactly when that is.