SIMON Callow, who comes to Ludlow Assembly Rooms on Saturday, March 19, is the author of books on Charles Dickens, William Shakespeare, Charles Laughton ... and Orson Welles. "I am drawn to very obviously much-larger-than-life characters and there is no one larger than life than Orson Welles," he says explaining the appeal of his subject, about whom he will be talking in Ludlow. "I am interested in the impact they make as people and secondly by their reach and ambition. In the case of Wells it's also about the disjunct between his extraordinary personality, charisma, power, intelligence and talent and what he achieved. He felt that very deeply."

Welles, Callow continues, had his head turned early with the word genius bandied about, but it wasn't just Welles whose head was turned. It seemed that the adults around him were similarly dazzled. "He was exempted from almost every obligation or discipline that others had to endure. He was sent to a very progressive school where the headmaster thought the best way to learn was by doing. So the school had a farm, an aerodrome, a radiophonic workshop and a theatre. Welles took to the theatre when he arrived and never came out.

"Leaving school at 15 he had no further education of any kind. He was so bright he could pick everything up."

"He was very lacking emotionally, and always said he'd never had a childhood, no period of slow growth and development. He was expected both by himself and others to present fully formed results immediately. That made him feel very alive and stimulated by drink and prescription drugs - and all before he became world famous with Citizen Kane.

"I can't think offhand of anyone in the 20th century who had a life like Welles's," Callow observes. "For me, it's quite compelling to find out what it's like to be a man like that or what it's like to be around a man like that."

Callow, of whom The Times said "Callow is not simply a terrific actor who happens to write - you could as well call him a terrific writer who happens to act,", reveals that "The writing came first, absolutely. I was an infant writer. I couldn't be stopped, but finally, at the age of 18, I realised I was only writing about myself, having done nothing, except sit in a pool of uncertainty!

"But I was not an infant prodigy. I always loved words and came from a gabby family who all talked well and at length, but they didn't read much. I was the first real book reader in the family.

"I had no idea of what to do with my life, except that I knew I didn't want to go to university. I had vague ideas of law or diplomacy but could see they involved vast amounts of work.

"I was in love with the theatre, but curiously, living in suburban London it didn't seem to be an option - I had no idea how you got to do that.

I already knew the Old Vic and was totally electrified by what was going on there - not just Laurence Olivier and Maggie Smith - the level was amazing. How wonderful, I thought, that everybody in the building, from the box office to the coffee bar, seemed to glow (??).

"So I just wrote to Olivier - I was a great letter writer and had written to The Queen with some success - carefully explaining what an excellent theatre I thought it was. He responded, saying 'if you love it so much why don't you come and work here, there's a job in the box office.'

"I saw all the plays and encountered actors for the first time, actors like Michael Gambon and Derek Jacobi, who were very nice, normal and straightforward - and I began to think that maybe I could be an actor.

"I felt I was too old, I was 19, to go to drama school and thought that I would, after all, go to university and went to Queen's University in Belfast. The drama group gave me a lead role as Tregorin in The Seagull on the basis of having worked at the Old Vic box office. I was dreadful and thought I'd better go to drama school, where I learned how to go about doing it properly and emerged as an actor.

"Then in 1984, as a result of my intense friendship with literary agent Peggy Ramsay, I was asked to give a speech, and I decided to give a full acount of what I thought acting was. I showed it to Peggy who said somebody should publish it and Nick Hern said it could be the basis of a book if Simon wanted to do that. Simon would and Simon did - the result was the bestselling Being an Actor. Since then, Simon has published biographies of Dickens, Shakespeare and Charles Laughton, as well as his four-volume biuography of Orson welles and will, he says, be 'foinessing' his biography of Wagner while touring his talk One Man Band, about Wells.

"I've also written a number of screenplays, which almost got made..." he adds.

And if he had to choose between writing and acting: "Writing was there first and will probably be there last. I can't see a reason for me stopping writing."

Simon Callow brings One Man Band to Ludlow Assembly Rooms on Saturday, March 19. To book, call the box office on 01584 878141 or visit ludlowassemblyrooms.co.uk