The first was Mrs Lees, who was an art teacher in the secondary school but came down to the primary to teach us once a week. I was always keen on drawing, but when I was about nine I remember bringing in an oil painting I had done at home to show to her.
Something about it must have shone. She nearly fell over when she saw it, and insisted that we go up to the secondary school to show it to Charlie Summers, who, as head of art, was the Almighty.
He looked at it and said: "Yes that's really good." He was enthusiastic but not bowled over, but Mrs Lees was hooked. She started to give me extra lunchtime tuition and made me do anatomical drawings over and over again to get the proportions right.
She looked like a pixie, not like a teacher at all. Her style was very Sixties, and she was always kind and encouraging.
Mrs Lees was friendly with Mrs McQueen who was my primary teacher when I was 11-years-old. Mrs McQueen always reminded me of Miss Marple in the way she dressed. Although she was a slight woman, she had a forceful personality.
I remember one day a group of girls had been bullying a wee Jewish boy, who was a friend of mine. When Mrs McQueen got to hear about it she got the culprits and made a real example of them in front of the class. It was so impressive to see her practically jumping up and down with rage. She was just exploding, saying: "Never, ever be racist towards anyone."
It was due to her that I got into the top stream in the secondary school. She was a great teacher, strict but really encouraging. She didn't just teach us to read and write, she taught us about life too.
Prestwick Academy in the 1970s was a very mixed comprehensive. There were lots of clever pupils and a bunch of nerds who bullied me terribly in my first year. I was a real cowardly seven-stone weakling and one family in particular made my life a misery - one of them used to get me by the throat and take all my dinner money.
We also had to undergo an initiation ritual handed out by the older boys. You had a choice; run the gauntlet, have your trousers taken off and thrown on the roof, or have your head flushed down the toilet. The thought of having to take off my trousers was worse then execution: I opted for having my head flushed down the toilet.
I hated school but I loved art, so as I got older I dogged off all the other subjects and just sat in the art room all day. Both Mrs Lees and Charlie Summers were encouraging and were instrumental in getting my portfolio together for the Glasgow School of Art.
Charlie Summers always had a great sense of humour. He seemed old to me then, but he was probably only about 50. He would give me a lot of work to do at home.
One day I showed him a pile of drawings I had been working on. As he looked through them he started shaking his head. I thought he was going to say they were rubbish. But he said: "God, I was never as good as this." That made a big impression on me and made me work even harder.
I went to art school after the fifth year and had a miserable time. After a year I was thrown out and joined the army. It was the best thing that could have happened to me. Although I was only in it for a year, the army taught me a lot. When I went back to art school I was able to stick up for myself.
I saw Mrs Lees a few years later when I was going through a difficult patch and showed her my portfolio. I got the feeling she was a bit disappointed - I think she felt art school had knocked something out of me. But later still, in 1990, I was doing really well and letting it all go to my head. I was staying at the Ritz Hotel in London with my wife when Mrs Lees telephoned out of the blue to congratulate me. She said it was the biggest moment of her life to see that I had achieved so much.
I wish I'd contacted her after that but I didn't. I know that she died soon after. But recently I did see Mrs McQueen. She came to an exhibition I had in Scotland. She's 85 now and still as bright as ever. Her first words were: "Where's the drawing you promised me?" I told her she could have the pick of the show. She chose a small drawing I did when I was in Bosnia which, as my materials were all stolen when I was out there, I had done in boot polish and candle wax.
I was totally knocked out to see her again. I know that if I were a teacher I would feel really jealous if a pupil were better than me, but what those three teachers had in common was that they were all totally selfless. For me they did an incredible job.
Peter Howson is internationally renowned as a figurative painter, in particular for his work as the official British war artist in Bosnia from 1993. Several of his paintings are on show until September 21 in the exhibition "British Figurative Art" at Flowers East Gallery, London E8. Tel: 0181 985 3333.