The festival brochure describes him as ‘the loveliest writer in Britain’ and it wasn’t hard to see why.

Alexander McCall Smith, author of the No 1 Ladies Detective Agency novels, 44 Scotland Street, Sunday Philosophy Club and Corduroy Mansions, among his 96 published books, is a sheer delight.

In the same way that his Mma Precious Ramotswe, lady detective of Botswana, generates a positive feeling of well-being and good humour, so does he.

He’s full of fun with a hint of mischief. He talked to Decca Atkinhead of The Guardian, and the audience, about his characters, the settings, and his method of working. He often gets up at 4am, writes up to two thousand words and then goes back to bed.

“The second sleep is terrific,” he said. “It’s the sleep of the smug.”

Mr McCall Smith is frequently writing books for two series at once. He said his books write themselves. “I get into a disassociative state, almost hypnotic, and my subconscious mind takes over. I don’t know what my characters are going to do next. But I suppose it’s all connected to my real life and waiting there in my subconscious to be used.”

The former professor of medical law said several women in Botswana claimed to be his model for Precious Ramotswe, a traditionally built lady who drinks Red Bush tea. He said the closest was probably Sheila Dinotshe Tlou, former Minister of Health for Botswana, and very good amateur actress. But Precious was an amalgam of traditionally built African ladies.

Interestingly, Mr McCall Smith said he was never able to see the faces of his characters. A member of the audience suggested perhaps he was writing from the inside the characters which explained why he couldn’t see the faces.

The author thought it was a very interesting idea and then declared he was going to have a sleepless night thinking about it.

The evening made you want to go out and buy all his books and spend a month doing nothing but read them.