A quarter of a century after Ayrton Senna was killed in a car bearing her family’s name, Claire Williams is reliving the tragedy of Formula One’s darkest day.

“About a year later I remember being in a pub,” she explains. “I don’t know how he knew who I was, but a complete stranger came up to me and said: ‘Your dad is a murderer’.

“It hadn’t really sunk in about how people might feel about the accident. That’s not what happened but I guess some people are ignorant.”

Senna was Formula One’s brightest star, a sporting giant, an icon in his native Brazil. But on lap seven of the ill-fated San Marino Grand Prix – a black weekend that had already claimed the life of Austrian Roland Ratzenberger – he ran off the road at 190mph and hit a concrete wall. He died instantly, aged 34.

Today marks the 25th anniversary of Senna’s death in Imola – the last time a driver was killed at a Formula One race. Jules Bianchi died nine months after his accident at the 2014 Japanese Grand Prix.

Ayrton Senna's career in pictures Show all 51 1 /51 Ayrton Senna's career in pictures Ayrton Senna's career in pictures 1983 After moving to England in 1981, Ayrton Senna went on to win the British Formula 3 championship, beating Martin Brundle (right) to the title. Getty Images Ayrton Senna's career in pictures 1983 The championship battle went down to the final round where Senna prevailed. Getty Images Ayrton Senna's career in pictures 1984 Senna made the step up to F1 with the Toleman-Hart team, having tested for the likes of McLaren and Williams. Getty Images Ayrton Senna's career in pictures 1984 Senna displayed his talent in the rain by taking second place at the Monaco Grand Prix. Getty Images Ayrton Senna's career in pictures 1985 A move to Lotus followed in 1985 where he clinched his first victory in his second race for the team at Estoril. Getty Images Ayrton Senna's career in pictures 1985 Senna finished the year in fourth place in the championship. AFP/Getty Images Ayrton Senna's career in pictures 1986 Sticking with Lotus for 1986, Senna again took two victories and finished the season in fourth. AFP/Getty Images Ayrton Senna's career in pictures 1986 An image of Senna, Alain Prost, Nigel Mansell and Nelson Piquet became one of the most iconic photographs of the sport. AFP/Getty Images Ayrton Senna's career in pictures 1987 Senna took his first victory at Monaco in 1987 in his third season with Lotus. Getty Images Ayrton Senna's career in pictures 1987 Senna would go on to win the Monaco Grand Prix six times - more than any other driver to date. Getty Images Ayrton Senna's career in pictures 1988 A third place finish in the 1987 season earned Senna move to McLaren alongside Alain Prost. AFP/Getty Images Ayrton Senna's career in pictures 1988 The move started what would become one of the greatest rivalries ever seen in F1. AFP/Getty Images Ayrton Senna's career in pictures 1988 Senna has captured the imagination of the Brazilian public who cheered his every move. Getty Images Ayrton Senna's career in pictures 1988 Senna beat Prost to the championship to claim the first of three world championships. AFP/Getty Images Ayrton Senna's career in pictures 1989 Prost and Senna continued to battle against each other in 1989. Getty Images Ayrton Senna's career in pictures 1989 But their relationship within the McLean team had unravelled to the point that the pair would not talk to each other. AFP/Getty Images Ayrton Senna's career in pictures 1989 Senna took his second victory in Monaco to start a run of five consecutive wins in the Principality. AFP/Getty Images Ayrton Senna's career in pictures 1989 Prost and Senna were battling for the title at the Japanese Grand Prix at Suzuka. Getty Images Ayrton Senna's career in pictures 1989 The pair crashed at the final chicane, putting Prost out of the race. Senna was given a push-start by marshals and rejoined to win the race. Getty Images Ayrton Senna's career in pictures 1989 But the Brazilian was disqualified from the standings and given a fierce warning by the FIA, handing Prost the championship. AFP/Getty Images Ayrton Senna's career in pictures 1990 Senna remained at McLaren for 1990 where Gerhard Burger replaced Prost, who has joined Ferrari. Getty Images Ayrton Senna's career in pictures 1990 Senna had thought long and hard about leaving F1 in the winter, only to return for the new season. Getty Images Ayrton Senna's career in pictures 1990 Senna's domination in Monaco continued. AFP/Getty Images Ayrton Senna's career in pictures 1990 Senna and Prost's batte stretched throughout the season. Getty Images Ayrton Senna's career in pictures 1990 Six wins throughout the season have Senna the lead heading into the penultimate race in Japan. Getty Images Ayrton Senna's career in pictures 1990 Senna knew that if Prost did not finish the race, he would regain the world championship. Getty Images Ayrton Senna's career in pictures 1990 The two went off at the first corner on the first lap after refusing to concede the lead to Prost, taking them both out of the race. Getty Images Ayrton Senna's career in pictures 1990 Prost's retirement meant that Senna had won a second world championship. Getty Images Ayrton Senna's career in pictures 1990 But Senna was clearly at odds with what he had done. AFP/Getty Images Ayrton Senna's career in pictures 1991 The 1991 season proved one of Senna's best as he finally won the Brazilian Grand Prix for the first time. AFP/Getty Images Ayrton Senna's career in pictures 1991 Another iconic moment in Senna's career came at the British Grand Prix when Nigel Mansell gave his championship rival Senna a lift back to the pits. Getty Images Ayrton Senna's career in pictures 1991 Senna sealed his fourth victory in Monaco. AFP/Getty Images Ayrton Senna's career in pictures 1991 Senna finished on the podium at 12 of the 16 grand prix in 1991. AFP/Getty Images Ayrton Senna's career in pictures 1991 Senna clinched his third world championship to join the greats of the sport. AFP/Getty Images Ayrton Senna's career in pictures 1992 Senna was not able to successfully retain the championship in 1992 but maintained his winning run in Monaco. AFP/Getty Images Ayrton Senna's career in pictures 1992 Nigel Mansell won the 1992 world championship as Senna could only manage fourth, with seven retirements throughout the season. Getty Images Ayrton Senna's career in pictures 1992 1992 also saw the emergence of Senna's last rival Michael Schumacher. Bongarts/Getty Images Ayrton Senna's career in pictures 1993 Senna drove one of the great drives to win the 1993 European Grand Prix at Donington Park as he overtook five cars in one lap. AFP/Getty Images Ayrton Senna's career in pictures 1993 Senna won his sixth and final Monaco Grand Prix in 1993. AFP/Getty Images Ayrton Senna's career in pictures 1993 Senna missed out on the title to the returning Alain Prost, who retired at the end of the season. Senna won his final race with McLaren before leaving. AFP/Getty Images Ayrton Senna's career in pictures 1994 Senna moved to Williams where he partnered Damon Hill. Getty Images Ayrton Senna's career in pictures 1994 Two straight retirements got the season off to a bad start, with Senna taken out at the first corner of the Pacific Grand Prix. Getty Images Ayrton Senna's career in pictures 1994 Senna remained at trackside to listen to the Benetton being driver by Michael Schumacher, which he was convinced was using traction control Getty Images Ayrton Senna's career in pictures 1994 Senna speaks with doctor Sid Watkins after the death of Roland Ratzenberger during qualifying for the San Marino Grand Prix. AFP/Getty Images Ayrton Senna's career in pictures 1994 The wrecked Williams left after Senna's fatal crash at Imola. Getty Images Ayrton Senna's career in pictures 1994 Senna Williams is taken back to the pits after his crash, with the Brazilian pronounced dead later that day. Getty Images Ayrton Senna's career in pictures 1994 Tributes were left at Imola in memory of Senna. Bongarts/Getty Images Ayrton Senna's career in pictures 1994 His funreal was attended by Brazilian president Itamar Franco among hundreds of thousands of mourners. AFP/Getty Images Ayrton Senna's career in pictures 1994 The 1994 season continued with a black cloud resting over it. Getty Images Ayrton Senna's career in pictures 2014 Senna's sister Vivianne has maintained her brother's legacy through the Ayrton Senna Foundation. AFP/Getty Images Ayrton Senna's career in pictures 2018 Lewis Hamilton was presented with a replica Senna helmet after matching his record of 65 pole positions at the 2018 Canadian Grand Prix. Getty Images

Sir Frank Williams, the team’s extraordinary founder, was cleared of manslaughter charges in 1997. The exact cause of the crash remains inconclusive.

“Frank never spoke to anyone about it,” Claire Williams, now the de facto boss of the British team, says.

“That isn’t his personality. He isn’t one for therapy, or having long conversations. He internalises and keeps it all in. That is how he has been brought up, but you can see the pain in his eyes every time he thinks about the accident.”

Senna was competing in just his third race for Williams, who were then the kings of the Formula One road. Nigel Mansell had galloped to the drivers’ title in 1992. Alain Prost won the championship a year later. Williams then landed the driver he had dreamt of signing.

“Ayrton was a God in our house and had been for many years, decades even,” says Claire.

“Frank had a love-affair with Ayrton. He got into his heart, got into his mind, and he always wanted to put him in his race car.

“Dad’s wish then came true, but it ended in the worst possible way.”

Frank Williams remains the team principal of a constructor which has won 16 combined championships. But his title is now largely in name only.

The 77-year tetraplegic has been consigned to a wheelchair for more than three decades after a road accident in 1986. He no longer travels to races, leaving his daughter Claire in charge. Yet on that fateful day in May, she was a 17-year old schoolgirl, preparing for her mock A-Levels.

Ayrton Senna with his trophy after winning the 1989 Monaco F1 Grand Prix (AFP/Getty Images)

“I was watching the race in my bedroom,” she says. “Dad was obviously away, and mum [Lady Virginia Williams] was watching it downstairs.

“It was just a horrific accident, and it felt as though something suddenly came over the house. It was really odd.

“Quite quickly, my mum came upstairs. I was due to go back to boarding school ?at 6pm that evening, and mum said you are going now. I knew then that something serious was going on.

“I was put on a train and sent away. My parents preferred to shelter us from it. They did that with dad’s accident and they did so with Ayrton’s death, too.”

Senna joined Damon Hill at Williams for the 1994 season (Getty) (Getty Images)

Tragically for Williams it marked the second time a driver had died in one of his cars. Piers Courage lost his life in a fireball inferno at Zandvoort, Holland, in 1970.

“It was an excruciating thing to happen to dad again,” added Claire. “He went to Ayrton’s funeral in Brazil which, from a safety perspective, we were all very worried about because Ayrton was an enormous hero and he died in our car, but Frank wanted to be there.

“We all then went to the memorial service in London. I’ll always remember my mother saying to me: ‘There will be no crying on this day, this is not your loss’.

Claire Williams has opened up on the impact that Senna's death had on her father (Getty)

“In our film [released in 2017] there is a scene where Frank is at Ayrton’s funeral, and I have never seen my dad look like that.

“There is an extraordinary line where he is asked how he felt that day, and he just says: ‘Far from well’.

“I think that says it all. I am sure he felt far from well for many, many, many years, and still today he won’t talk about him.

“He will talk about what a great man Ayrton was, and what a great driver he was, but nothing to do with the accident.”

To this day Frank Williams will not talk about the crash that killed Senna (Getty) (Getty Images)

Despite the tragedy, Williams carried on. David Coulthard took Senna’s seat as Damon Hill became the team’s lead driver. Hill fell just one point short of beating Michael Schumacher to the championship.

“I am sure there were days when dad may have thought I don’t want to go racing, I want to hide under my duvet,” Claire concludes.

“You just want to stop sometimes, and that was the hardest thing. But people in this sport are made of stern stuff, and Ayrton probably wanted us to keep racing.”