I didn't have to go to his studio; he came to paint me at home. He seemed to come a hundred times - he was really very painstaking. At the time he was very young, in his early twenties, and he was constantly asking me to keep still. I said I couldn't be stiller - he said no, you must be absolutely still. You don't understand, he said, my whole career is at stake here - he was half joking, but it was very important to him.
I had never sat in this kind of intense manner; I had only sat briefly for a portrait before. I played a lot of music and we occasionally chatted; but he was concentrating very hard. I am sitting in the chair I sit in all the time in my study. I just sat back and thought about life, death and everything; I was quite relaxed.
I remember when he had only done the head itself, my head, and I wondered what was going to be in the background. He said he hadn't the faintest idea - I was looking at something quite naked as the head was very small on the bare canvas. When I saw the painting of my head I said to him, I sometimes smile you know. You can't have everything, he said.
One day I came into my study and Justin had left the finished painting. I suddenly saw this red background and papers everywhere. There are papers like that in my study, but not a red wall.
I like the composition and the way it is painted - I like it and think of it as a painting, not a portrait. It was a happy experience sitting for him.
My wife likes the picture. I believe there are other aspects of me, and I find it very difficult to judge the nature of my expression in the painting. I suppose it is pensive. But it was an agreeable experience to sit for him - he was charming.
Harold Pinter's 1957 play 'The Birthday Party' opens on Tuesday (Piccadilly, W1 0171 369 1733). His 1992 portrait by Justin Mortimer hangs at the National Portrait Gallery, WC2 (0171 306 0055).