I nearly said no to doing the portrait because he said it would take 10 hours, and it was the most awful thought, sitting still for so long. I have been painted before, but it only took half an hour. I don't think I would want to go through sitting for another portrait now; I wouldn't want to do that again.
Tai-Shan Schierenberg had a very cold studio just behind the White House in Regent's Park. It's a wonderful circular building, and it's really strange. I actually used it as the set for a TV play after going there to have my portrait painted.
When I got there I asked, "What do your sitters usually do?" He replied that they normally ran screaming from the room! So I sat for him, but I couldn't read, and he didn't talk. There was a one-bar electric fire and it was really cold, just sitting still. Sitting still is really tedious.
He actually took lots of photographs, and the final portrait didn't take 10 hours - more like five. I can't remember how many times I went to his studio - about three or four perhaps.
In the portrait, the person behind, in the frame, is him - a mysterious version of him. It's like many Italian works, when the artist has actually painted himself into the painting. He's also fond of dead birds, so there is one of those in the portrait as well, hanging on the wall.
I think, luckily, that it's a really good picture, a really good modern work. I'm very proud of it, and he's an excellent painter, rather like the Euston Road School. I like the style of the painting: there's lots of paint splashed around - it suits my personality.
John Mortimer is a barrister, playwright and author. His 1992 portrait by Tai-Schan Schierenberg hangs in the National Portrait Gallery, London, WC2 (0171 306 0055).