Revelations: "You are, aren't you?" she exclaimed. "You are Miss Gertru de Stein." I nodded and signed her programme. Next she asked: "How is Miss Toklas?"

The time: 48 hours in May 1996 The place: Kent The man: Tom Baker, actor and former Dr Who

Last year I was terribly out of work; I couldn't earn a living as an actor, so I decided to write something about my childhood. I took a bit into my wife and she laughed her head off. Gradually I wrote more and more, but some parts that I thought were funny - how my first ambition was to be an orphan - she thought were sick and desperately sad. During the war, if somebody had a tragedy in Liverpool the Americans would send them nice clothes and fantastic goodies. Being extremely poor I would ask "Why has he got nice clothes and I haven't?" and they would reply: "Because his mam died" So privately I prayed that a bomb would drop on my mam. It wasn't that I didn't love her, because I did passionately, but goodies can de-humanise a child.

After a while I had a manuscript and I phoned my voice-over agent - I'm very persuasive in minor advertising and audio visual commentary: "Jackie, how does one go about getting a publisher." She phoned a friend in Talking Books who spoke to her boss and within 40 minutes, Jackie was back on the telephone with the news that Harper Collins would be delighted to read my manuscript.

So I put on my passionate sincerity voice and called their head of non- fiction. I was put straight through which made me feel rather uneasy. He explained how delighted they would be to read the manuscript. "Marvellous ," I said "I'll bring it round. Where are you?" "Hammersmith", he confessed.

"Forget it," I said, " I don't want to be a writer anyway. A man of my age can't be seen in boring Hammersmith." Yet he was so keen that he agreed to rush straight over to the Groucho Club in Soho. Twenty minutes later he bought me a coffee - which I didn't think obligated him too much and I gave him my envelope. Off I went for a beer. It's now almost 24 hours since my first inquiry.

When I got home at 4.30pm my wife was waiting with the news that Harper Collins wanted to buy my manuscript. I thought the world had gone mad. Still out of work, Harper Collins asked me to go to a dinner and talk about my book. I recounted an experience at the Chelsea Flower Show where a tiny little woman tapped me on the shoulder. You could tell that she once had enormous eyes, now very small because the lids were so heavy that she couldn't raise them anymore. "You are aren't you?" she exclaimed; people often say that to me. So I said "Yes I am." "Oh Miss Stein, Miss Gertrude Stein," she gushed. I'm regularly mistaken for Jonathan Miller, or Jon Pertwee, if they really want to torture me, but this was a new low. I looked at what must have been a retired lesbian and instead of saying "Fuck off you mad old cow," I nodded and signed her programme: "Cordially yours, Gertrude Stein." Next she asked: "How is Miss Toklas?" "Still teasing Henry Miller," I retorted.

My stories were a great success. Harper Collins were delighted because my audience were buyers and wholesalers. Being shameless, anxious and out of work, I covered similar functions across the whole of the UK - no one was omitted. If people were ill, I used to go into hospitals to tell them about my book.

I've suddenly realised to my amazement, I'm about to be a famous author. They've printed 80,000 copies; I'm going on a 50-city publicity tour. Now I get letters from girls with double-barrel names, which has always been good for my libido, asking me to come and talk at literary festivals. I went through a phase where I could only shag girls with double-barreled names - twice the pleasure, I thought.

I come from a very loose family but writing this autobiography has made me pick up things from my past. I haven't seen my brother since my mother died donkey's years ago. I look forward to seeing him on this tour. As an actor I'm very aware of how short of identity I am. Being noisy just masks my inadequacy; I lack a personality. The uncertainty about who you are is part of the impulse to be an actor.

I've learnt nothing about myself, just how to pace myself a little bit more and how to value my wife and home. I think I might have improved a little bit there. What ever I do I'm always an actor: this play is called "Promoting A Book". If they won't give me a job at the BBC I'll invent my own drama. I thrive on anxiety and insecurity. I don't believe in a state of nirvana; if it exists I want nothing to do with it.

All I have in my life is my anxieties. My irrationalities make me laugh at myself, because I am ridiculous. I don't have friends, being an actor I'm too self centred to have the gift of friendship which requires a degree of self-sacrifice, but what I'm really looking forward to is imagining how astonished my few acquaintances will be about the idea of Baker writing a book - especially if I get a good review.

One sign of some maturity is my third marriage where I have voluntarily demonstrated my commitment by investing in a home. You can't both have a flat only meeting for casual shags and call that a deep relationship. We've bought a beautiful house together with a garden, lovely cats, a moor and cars; that's a step forward. When I walk through Soho and they call out from the Coach and Horses: "Come and see us" I go home instead.

`Who on Earth is Tom Baker' is published by Harper Collins, available now at pounds 17.99. An audio book - read by Tom Baker - will be available from October 20.

Interview by Andrew G Marshall