Just six months later the marriage collapsed after she dumped him for one his ­wedding guests and best friends, Stephen Hall.
In 2011 she said she and Clarkson rekindled their relationship in an illicit seven-year affair behind his second wife Francie’s back.
Following the lifting of an injunction Clarkson obtained to silence her claims, Alex said “I still love Jeremy. He got the injunction because he had something to hide. I can prove we had an affair. The truth will out. We did have an affair for seven years.”
She said: “Four months after I left him I realised I’d made a mistake and it’s had a huge impact on my life and has affected me hugely for the rest of my life. Having Jeremy Clarkson as my ex-husband has had a huge influence on my life. I had no idea how great an influence that was going to be.”
Alex’s fixation with Clarkson was so ­overpowering it ended up wrecking her second marriage to Stephen.
The couple, who have two children ­together, married in February 1993, two months before Clarkson wed Francie. But Alex’s second ­marriage lasted barely four years.
Clarkson, 51, wrote about Alex in his ­newspaper column saying: “In 1990, after six months of marriage, she ­admitted to a number of flings and left me for another man. Fifteen years ago, when I started to appear regularly on television, she began to demand money for her silence.”
The motoring guru, left with a legal bill that could hit £100,000, had insisted in court there was no truth in Alex’s account of events that they met regularly for clandestine sex. And he maintained that Alex had ­attempted to blackmail him and Francie for £300,000 to keep silent.
She says: “I had the courtesy to tell him that I wanted to write a book and his reaction was to slap a super-injunction on me. I had no ­intention of writing anything nasty about him, I was going to be ­completely lovely about him. I wasn’t going to mention the affair. I’ve got a ­tape-recorded conversation where I said I wasn’t going to mention the affair. I was going to do my book, my life and the impact his fame has had on my life. There wasn’t that much to do with him, I wanted to write my story. He’s shot himself in the foot. If he hadn’t wanted any ­mention of the affair then he shouldn’t have taken the injunction out.”
Clarkson, however, is adamant Alex told him she WAS going to write about the affair, which he denies. Their conversation prompted the injunction, which he says he took out to spare Francie and his family embarrassment.
In her That Sunday Night Show interview, Alex points out she was with Clarkson a lot longer than the marriage. “I was with him from the age of 17, he was 22,” he says. “From two weeks into the relationship we lived with each other, worked with each other all the way through for eight years. It was a long relationship at a very young age where you’re influenced totally.”
And she boasts: “You’re going to learn masses from my book. Other women will definitely relate to it because I’ve been through so many life experiences.”
It is believed the book may detail her first dates with Clarkson. He proposed to Alex on a freebie trip to a motoring launch in Venice.
She and Clarkson married in a village church near her family’s Hampshire home in September 1989.
Then after a change of clothes they headed off on honeymoon to Mauritius.
Clarkson reputedly spent most of the trip complaining about how hot it was and ­staying in the shade to avoid sunburn.
“The honeymoon set a bit of a pattern,” said the friend. “Alex wanted someone to nurture and pamper her, buy her flowers and make a fuss of her. But Jeremy wasn’t that kind of guy.”
Then, half a year into the marriage, Alex confessed to Clarkson that she had begun seeing Stephen.
“Steve was much happier talking about his ­emotions,” said a source. “He became a shoulder for her to cry on and then it ­progressed into a ­relationship.”
Clarkson was, we can reveal, in despair at the split.
Asked in an interview about the worst way he’d been dumped, he replied: “The worst way anyone can dump you is by going off with your best friend.”
Alex has told friends she and Clarkson became lovers again after she split with Stephen, meeting at ­Clarkson’s London flat.
When arguing for an injunction against Alex at the High Court last year, Clarkson’s lawyers said it would be “very ­distressing” for Clarkson if Alex’s claims were made public.
Now, though, he ­appears resigned to doing continued ­battle with her out in the open.
“She now has the right to say what she wants,” he said this week. “And you can choose whether or not to believe her.”