Alex Hall: 'Only Jeremy Clarkson and I know the truth. Now we can both put our side across'

Alex Hall has made plenty of mistakes. Falling in love with Jeremy Clarkson as a teenager was, you might say, the first. Ending their marriage by leaving him for another man was, she now says, the worst. But as the Top Gear presenter's 46-year-old ex-wife prepares to write a book about her life in his shadow, you can't help feeling she's about to make yet another.

Ann Widdecombe has called Hall the "latest in a long line of kiss 'n' tell merchants ... looking to turn her revelations into filthy lucre". Others have wondered why anyone would be interested in her story, were it not for her association with Clarkson. Her motive, you have to assume, is money, self-promotion or revenge. Perhaps a mixture of all three.

Where Hall's story takes on a wider significance than the average salacious red-top tale is in her experience of being the subject of a super-injunction. It should disturb anyone who cares about freedom of expression and the age-old assumption enshrined in British law that someone is innocent until proven guilty. For since September last year, she has been legally gagged from saying anything about their relationship, simply because Clarkson could afford to persuade a judge that his right to privacy was greater than hers to free speech. Until two weeks ago, when Clarkson abandoned the highly expensive injunction, Hall could have gone to prison for merely speaking about their relationship. In April, she wrote an article for this newspaper, but her identity had to remain hidden.

Now she is talking freely, though it's not easy to work out who Alex Hall really is: a bullied victim of a rich and powerful man, or a shameless opportunist. We meet at the Institute of Directors in Pall Mall, a £300-per-year club for business directors where she bases herself when in London. She is tall and, on first impressions, confident, though the events of the past year have taken their toll. She reveals herself to be emotionally fragile, and when she talks of her feelings for Clarkson, she breaks down in tears. She still loves him, she says, and is unable to find another man like him. Because of her feelings for him, she has been unable to hold down a meaningful relationship with another man. The irony is that she left him in the first place.

All she wants now is to put across her side of the story. The obvious cold-hearted response is: who cares? But in the Surrey circles in which she moves she says her name has been sullied by years of rumour and innuendo. "Our network of friends turned against me, not because of anything I had done, but because of what he and other people said about me."

It began in 2003, when news of Clarkson's indiscretions with another woman broke. A newspaper then approached Hall and offered her £150,000 to speak about her ex-husband, which she turned down.

Given that she had by then divorced her second husband, Stephen Hall, and was a struggling single mother of two children, rumours started swirling that she had blackmailed Clarkson with a threat to sell her story, prompting mutual friends to turn against her. "It was about perception. I was shut out and I need to get some kind of closure on it."

Born in Hampshire in 1965, Hall met Clarkson two weeks after moving to London in the late summer of 1982. She was 17, he was 22 and working as a rep and living in a squalid white room in Onslow Gardens, a leafy square in South Kensington. "It was just a bed in the middle of the room, beneath which he kept this enormous casserole full of cigarette butts. It stank, but he was proud of those fag ends."

Only two weeks after meeting they were living together. Hall was instantly attracted to Clarkson's self-confidence and forthright views. "He is just as seems on TV. He's a northerner, so he calls a spade a spade, and comes from a big, boisterous family where you were encouraged to have strong views. He also has a fantastic sense of humour. Life was just about having fun and laughing."

In 1989, after seven years together, they got married. But in 1991 she left him for his friend, Stephen Hall. Clarkson was devastated. After four months with Hall, she realised she had made a mistake, but by then it was too late, for reasons she will not elaborate. "I can't go into that because I have to think of my children and other people, but leaving Jeremy was the biggest mistake of my life. I still love him – I always have – but I believed that if you make your bed you've got to lie in it."

She remarried in 1993, and had two children, though the marriage lasted less than four years. Clarkson married a mutual friend, Frances Cain, who became his manager. Then, in 1999, Hall resumed contact with Clarkson, and so began their alleged 10-year affair. They would meet at his Fulham flat for curries and romps on the sofa. "It didn't feel wrong because he was my ex-husband," she says.

But in the age-old tradition of mistresses who long to be wives, Hall tired of being treated as a second-class citizen. "He would walk on the other side of the road so that we weren't seen together. In the end I felt I was being used. After 20 years, I got fed up with being the one who quietly supported him and put up with everything."

Plagued by the rumours of blackmail, and wanting to move on from her years in love with Jeremy, she decided to write a book as a process of catharsis. But says she had no intention of writing about the affair. "I admit that I had been given a voice by being Jeremy's ex-wife, just as his mother Shirley had when she wrote her book. But my intention was not to hurt him. I wanted to write a book to get over Jeremy and put all that behind me."

Although the book is not yet written, she has 20 years' worth of notes, and says it is now just a matter of putting them in order. If the book is about catharsis, why not write it but not publish? "That's exactly what Jeremy said. But I want to clear my name in Surrey." She likens her story to that of Prince Charles and Camilla, a series of cock-ups that meant she and Jeremy ended up with the wrong partners. But unlike that soap opera, which, despite the obvious tragedy has had a happy ending, there's no likelihood of Hall and Clarkson living together happily ever after. "Only Jeremy and I know what the truth is. Now we can both put our side across." As for who to believe, that's for us to decide.