If there were doubts about Tommy Byrne's suitability for the corporate demands of Formula One, they were erased in a hedonistic blur as a manic-depressive, alcoholic, bisexual playboy tried to shoot him at a post-race orgy. “I'm attracted to sick f***ers,” he says.

Few people outside Formula One will remember Byrne, but he was almost brilliant, an older version of Lewis Hamilton. He has largely been portrayed as an embittered has-been fuelled by anger and resentment, but he says that he has long buried the ghosts of his fabled test drive for McLaren. As for Julian Randles, his Theodore team manager in his one year at the back of the Formula One grid in 1982, he says: “Sure, I asked if I could get the guy killed, but I wouldn't have gone through with it. I hated him because he'd ruined my life, but ten years later I had to lick his a*** to get a drive in the States.”

There is a beer-stained romance to how Byrne avoided becoming a household name, and to get near the truth you need to steer a course between his unbridled ego and the poker-faced disdain of the power brokers. However, Eddie Jordan said that he was “the best of them all”, John Watson, the former McLaren grand prix winner, hailed his “phenomenal talent” and Gary Anderson, the Formula One designer, said that he was “as good as anyone” before adding a footnote about Byrne skipping a session at Donington for a liaison with a woman.

Byrne, 50, denies that story and says that myths have muddied history. What is clear is that the test for McLaren at the end of 1982 evinced a natural talent to match that of Ayrton Senna then and Hamilton now. Byrne denies that he told Ron Dennis to “stick his car up his a***”, saying that the McLaren team principal was not even at Silverstone that day. That was probably just as well, given that Byrne turned up with a woman he had just chatted up, albeit he is at pains to point out that she was not a prostitute, “although she did look like one”.

After struggling all season with the makeweight Theodore, the test was stunning, for driver and bystanders. The future was bright, but then the phone did not ring. “I was never going to drive for McLaren,” Byrne says. “I was not their type. Anyone who knows Ron Dennis, knows that. People say I did not apply myself, but I applied myself to win six titles in four years and get to Formula One. Trouble is, they want yes men, people who will smile when they're told to.

“I look at Lewis Hamilton and he is very good, probably the best driver out there. He overtakes and says, ‘Don't mess with me.' He will probably win more than one championship and good luck to him. Unfortunately, he drives for Ron Dennis and there are a lot of people who don't like Ron Dennis. I could never have done what Hamilton has done. I could never toe that line, let them drum your personality out of you.”

Interestingly, his critique of the sanitised paddock explains why Dennis was right in believing that a “knacker from Dundalk”, as Byrne refers to himself, would have constituted a huge risk. Byrne was never afraid to speak his mind and so Senna, deified since his death, gets both barrels.

Both drivers burst on to the scene at the same time, with Ralph Firman's Van Diemen team, and their cultures clashed, the obsessive Brazilian backed by a family fortune against a man who used to steal from the church box. The way Byrne tells it, Senna saw him as an obstacle to his ambition. There were arguments - “he called me a f***ing thief” - but when Senna succeeded Byrne as British and European FF2000 champion in 1982, his star was in the ascendant while the Irishman's imploded into a black hole.

Byrne portrays Dennis as a snob who sneered at his background, but turning up to the Formula Three prizegiving in a drug-induced frenzy - “I laid out two ginormous lines and snorted them” - suggests that caution was required. He eventually went to the United States and then Mexico. There he met Orchio, the man who nearly claimed his life at a party filled with prostitutes.Byrne said that he wanted his book, Crashed and Byrned, to be funny, but there is an undercurrent of sadness amid the “what ifs”.

He teaches driving in the US, but a few years ago his past paid a visit when he bumped into Tony Vandungen, who had been a mechanic on his fabled McLaren test. “He told me he had doctored my pedals not to give me full throttle,” Byrne says. “I asked why and he said they didn't want me to go faster than Thierry Boutsen. They thought I was too cocky.” Vandungen confirmed Byrne's take.

It is an intriguing postscript to a story that never happened. In his only spell in a quality car, Byrne was a one-lap genius, but now he is relishing passing on his knowledge. So while Hamilton, Dennis's protégé, prepares for another grand prix, Byrne, the errant pupil, is a teacher bonded to outsiders. “I like to get hold of these crazy f***ers, the people nobody wants,” he says. The people like himself.

McLaren may have made the right choice, but you cannot help feeling that it is our loss.

Crashed and Byrned by Tommy Byrne is published by Icon, priced £10.99.

Chequered career

Born May 6, 1958, Drogheda, Co Louth

Achievements: 1981 FF2000 British and European champion. Stood in for Ayrton Senna at Formula Ford Festival, the unofficial FF1600 world championship, at Brands Hatch and won

1982 British Formula Three champion. Makes debut for Theodore Formula One team. Two races, three DNQs, no points

1983 Races for Eddie Jordan Racing in European Formula Three Championship

1988 Finishes second in American Racing Series

1989 Finishes second again

1992 Retires

2008 Teaches defensive driving in Ohio