Antonia De Sancha: I kissed, I told, and then...

A head emerges through the open window of an upstairs flat in a scruffy corner of north-west London. "The doorbell doesn't always work," the woman offers as explanation to my vain attempts at getting it to sound. There's no mistaking the face. Ten years after her notorious affair with the former Tory MP David Mellor, Antonia de Sancha is still striking.

The once severely scraped-back hair has been replaced by clutches of Medusa-like brown curls flashed with silver. Her tight faded jeans and cropped white top reveal the same slender figure that Mellor couldn't resist, a temptation that led to his resignation as Secretary of State for National Heritage.

At the door, de Sancha, now 40, apologises for the state of the bare stairs, down which is floating the undeniable pong of joss sticks. She shows me into her India-themed sitting-room, where antique saris hang from a wall and an enormous hunk of gypsum and amethyst decorates the coffee table. Among a stack of art books in the corner is one entitled Forbidden Erotica.

De Sancha hasn't talked publicly about the affair for years. Little wonder, considering its impact. Fearful of the public's reaction, the one-time fiercely ambitious actress has only once dared to face the camera again (a non-speaking part in a television play in 1995). She has never taken on long-term employment, wanting to maintain what little anonymity the years have afforded her. The three-month liaison also contributed to the failure of her subsequent marriage.

Despite everything, de Sancha, who has since spent a lot of time "working on" herself, insists she is happy. She is now able to laugh about the affair, the aftermath of which led her to consider suicide. In a lighter moment, when I tell her there is one question that comes to everyone's lips whenever the scandal is mentioned, she knows exactly to what I'm alluding. "What the hell attracted me to him?" she asks, smiling. "That's a question I sometimes ask myself on very rare moments at awkward times in my life. Oh God," she says and sighs. "Absolutely nothing attracted me to him physically. But sometimes you can meet somebody who is not an oil painting, but you forget about that and it's no longer important, it's who they are and what they're like inside."

The affair started in April 1992 when the pair went out to dinner with a mutual friend, Paul Halloran, a journalist for Private Eye. "Paul had to go, so he left and we just started talking and got on really well, and one thing led to another. He called me up and that's how it started." What did she see in him? "He was witty, charming and just great fun to be with. The excitement was, to be perfectly frank, from being with somebody who was in a peak position of power. Though it was more than that. He made me laugh, I think I made him laugh." She refused to consider the potential consequences. "I was too excited. I took every day as it came. Now I would, but I would never get myself in that position again."

At the time, Mellor, then 43, had been married to Judith for 18 years, and they had two children. "Of course I thought about them, but in those days I was a lot more selfish. I had never experienced my partner having an affair, so I never really understood the pain it could cause. I was probably in denial about the pain I would cause his wife and family. And I was very focused on my career. That, by the way, bears no relevance to my association with him." (The Rada-trained actress had just returned from a tour of the States and Canada playing Clytemnestra in Aeschylus' Agamemnon.)

An affair suited her perfectly. "I didn't involve myself in long-term relationships; I didn't really have time and deep intimacy really scared me." She believes the fear stemmed from having lost both her parents in her mid-20s. In 1984, her Spanish father died of pneumonia; around 18 months later, her Swedish mother committed suicide while suffering severe depression. It was four days before de Sancha was to start at Rada. "The shock was so much I didn't believe she was dead. I was suddenly on my own, which was frightening. In a way, I never had time to mourn my mother."

The affair was "exciting, fun, busy" and one, she claims, of mutual love. "It was new to me and I love to experience everything. I'm someone who has a great hunger for life and experience. And I was seduced by the power."

It wasn't long, however, before their cover was blown. The couple were conducting their affair in a London flat lent to de Sancha by a friend, Nick Philp. "The person who leaked the story was Nick Philp. I've known him over the years, we weren't very close but we were friends, and because I was excited about this thing I told everybody. I was terribly naive. I was thinking 'God! I'm so excited I'm having this affair with this politician!' I was completely open. Big mistake." Philp tapped his own phone and gave the resulting tapes to The People, who installed a reporter on the patio to listen in. The People splashed the story on 19 July – 10 years ago this week – under the headline "Fun Minister Is 'Exhausted' By Relationship".

"It was an emotional rape," says de Sancha. "It's the most horrible thing, all the conversations I had had with my friends, very personal conversations, had all been bugged, and to know that there were all these awful people listening. The intrusion is like you're standing there naked and someone is cutting your body up very slowly. What upset me was that people thought that I had blown the story myself in order to be known. Why would somebody with a reasonable amount of intelligence, and hopefully a reasonable amount of talent, suddenly go out with a politician, blow the story, knowing full well by doing that you are certainly not going to gain respect?"

Indeed. De Sancha was dubbed a "soft-porn actress" after it was revealed that she had played a one-legged prostitute in a film in which she had simulated sex with a pizza delivery man. Topless photos appeared in the press, as well as details of her having worked as a receptionist in an escort agency and as a waitress in a hostess bar. "Nothing nice came out," says de Sancha, drawing on a cigarette. "Why did they want to give me such a bloody hard time? I had really done nothing wrong, other than have an affair with someone who happened to be married. OK, that's not very pleasant, but it wasn't manipulative or vindictive, or a nasty horrible move on my behalf."

De Sancha, acutely aware that the papers were making money out of the story while she wasn't, employed the services of Max Clifford. "I couldn't deal with it on my own. I was an emotional wreck, totally vulnerable. Everybody wanted a piece of me. I suddenly realised my career was ruined." Cringe-inducing details of the affair were revealed, including Mellor's alleged penchant for spanking, having his toes sucked, and the scandal's most memorable image: that of the football fan minister having sex in a Chelsea strip (minus the shorts). Was it true? "Basically the Chelsea strip was made up," de Sancha eventually admits. "I went along with everything at the time. It was almost like I was having an out-of-body experience." And the spanking and toe-sucking? "It didn't happen."

Mellor, after further revelations that he had accepted a "freebie" holiday from the daughter of a PLO leader, resigned that September, and lost his Putney seat in the 1997 election. De Sancha, who made about ?30,000 from the newspaper deals, went to France then returned to London at the end of the year, where she met her husband-to-be, Clive Hagar, a dentist. They married in 1994, but divorced a couple of years ago. "We separated because of the trauma. I couldn't deal with it very well and I brought it into the relationship. I took out a lot of my anger and frustration on him. I was always seen as something I never was. And that goes back to childhood as well. Everything came to this big lump that I hadn't worked out."

Following the affair, de Sancha worked for a few months as a contributor on Talk Radio, wrote a few articles for the left-wing magazine Scallywag, and did office work. She imported materials, rugs and jewellery from Thailand, where she lived for a while, and also spent a year in Rajasthan, working in mosaics. Now she imports Indian textiles for private clients. "I was nervous of getting a regular job because of what other people might think of the bad press that came out. My levels of concentration were minimal, there was so much to sort out in my own head. I still have the acting bug, but there's that thing of wanting to remain anonymous. Acting was my life. I got a lot of offers, but I just wasn't ready."

Bizarrely, Mellor is now a columnist for the very paper that exposed him. He also hosts his own show on Classic FM. He and Judith divorced in 1995, after his affair with Lady Penelope Cobham, who left her husband for him.

The former actress says she never thinks of the former "Minister of Fun". They last saw each other about a year ago, when they both happened to be dining at the same restaurant. Ironically, de Sancha was with Paul Halloran, the man who had introduced them. "David was walking down the stairs and I saw his knee cap which I recognised. He saw me and he saw Paul and he freaked out. He went to the loo for about 20 minutes, then went and sat down at his table. I have never seen a man eat so quickly. He totally ignored us and, as he walked past us, Paul said: 'Hello David, say hello to Antonia'. He spluttered hello, went bright red and ran up the stairs. It was just pathetic."

So does she regret the affair? "I don't regret anything because it has made me who I am. The experience was so powerful I feel good about myself now, whereas then I didn't. It's made me into a better person. I'm a lot calmer, and a lot more at peace with myself. I'm a lot more accepting, understanding and able to deal with things. I know exactly what I want and don't want. Of course I wish it hadn't happened. But it happened and I think everything in life happens for a reason. We all make mistakes, and hopefully we become better and slightly wiser as a result."