Katherine Jenkins, opera singer. Mr Thomas at Alderman Davies primary school, Neath

We all loved him; he was such a warm man, but also firm. Even though I was only four, I think I realised it was not every headmaster who sat down and played the piano with his pupils. I still see him when I go home to Wales because he goes to the church where I was a chorister, next door to the school. He has become a family friend.

Julian Clary, comedian. Frances Hanley at St Benedict’s, now Ealing Abbey, London

My best teacher of all, my own Jean Brodie, was Frances Hanley, who also taught English. She was glamorous, young and beautiful with flowing red hair. Her classes were a joy and she inspired us all. She was full of encouragement. On one end of term report she wrote of me: “The sky’s his limit.” When she left to have children I was devastated.

Emma Richards, yachtswoman. Neil Spurway, sailing coach

From the age of 12, I took sailing lessons at Cumbrae, an island west of Largs. I joined the Scottish Optimist sailing squad and Neil was our coach.

There were probably 12 of us in the squad, about four girls and eight guys.

Neil organised long weekends where we’d go to points such as Garroch Head and practise sailing techniques in unfamiliar waters with different tidal flows. We went out in a little coach-boat with Neil, then he set exercises for us, such as racing around a course, or sailing backwards between two marks, or sailing without the rudder, which meant you had to steer purely on the trim of the boat.

He was a real father figure with his white beard and white hair. It was a great joy to be coached by him because he believed in everybody he worked with. He was the best kind of coach for us at that age. He motivated us by making it fun while we learned to sail, and he encouraged us to be competitive, which I definitely gained from.

Professor Heinz Wolff, emeritus professor of bioengineering at Brunel University. Mr Jacques at City of Oxford high school, Oxford

He was a small, near-bald, slightly untidy bachelor, who lived in digs near the school. Moderately deaf, he wore what for the 1940s must have been a state of the art hearing aid, which had an external earphone held in place by a swingy piece of metal over his head. Harry wore a gown sometimes, with many holes burned into it and frayed at the bottom. Very much a demonstrating chemist, he taught chemistry of the kind written about in Every Boy’s Book of Chemistry.

Andrea Levy, author. Alison Fell at London’s City Lit

People laugh at me now when I say I never read a book with pleasure till I was 23. But Bleak House, The Mill on the Floss: they just made my heart sink and my mind go blank. The A-level required a level of understanding that just went over my head. I bought pass notes, and that’s how I got an E grade for English.

Much later, in the 1980s, I had a friend in Australia who said my letters were really good, that I wrote well. I started writing stories for teenagers and then I met someone who was in a writing group. They told me about the City Lit and a course, Beginning to Write, with Alison Fell. You came with something, you read it out and people talked about it. I attended for six years and had my first book published. I saw Alison after the Orange Prize when I was doing a reading at Middlesex University; she came up and said I deserved it. Alison taught me everything I know about writing.

Sir Alan Sugar, entrepreneur. Mr Grant at Joseph Priestley school, East London

I remember Mr Grant, the maths master, because even though he gave up on me, I managed to pass my O-level. He was a real eccentric. We used to call him Theta Grant because he made us laugh when he wrote the Greek letter theta on the blackboard. He was accident-prone. He’d come into school with his face smashed in or a broken arm. There were all sorts of rumours going round, but we never found out the cause of his injuries.

When I discovered that the maths O-level syllabus involved something called calculus, which was supposed to be really difficult, I was fascinated. I’ve always enjoyed a challenge. I’m a quick learner and have a photographic memory. Within three or four weeks, I became the whiz-kid of calculus, which got me through the exam. Grant couldn’t believe it.

Ashia Hansen, triple jump champion. Mr Goody at Susan Lawrence junior school, London

The teacher I remember was Mr Goody. He was the first one who spotted my talent and introduced me to athletics. There was a whole-school race where we would line up and race across the grounds. I started to run and accidentally tripped up the fastest girl in the school. I finished the race, and won it, and everyone hated me even more. Then they re-ran it and I still won. Mr Goody saw me running and took me to the local racetrack. It was great. I loved running and jumping. I used to love all the sports we did at school such as rounders and roller-skating, and I was in the cricket team.

Danny Boyle, film director. Mr Unsworth at Thornleigh college, Bolton

He was a very proper, orthodox teacher, except that he was passionate about his subject, particularly Jane Austen. He took this bunch of 16-year-old lads and introduced us to the most boring novel in the world: Northanger Abbey. But somehow he made us all not only appreciate it, but fall in love with it.

He made English my favourite subject. I was reading Ian Fleming novels before he started teaching me, but he made me appreciate the artistry in writing and the expression that was possible through it. There was something mesmeric about his devotion to the subject.

Hardeep Singh Kohli, writer and comedian. Mr Renton at St Aloysius Jesuit school, Glasgow

Very Glaswegian, married with seven or eight children and in his late thirties, he always wore the same battered corduroy suit, which I’m sure was 50 years old when he bought it. There was always stuff in his pockets; not just mints and tissues, but things like the tube of a Bunsen burner he’d just found on the floor. He had the comforting smell of a teacher.

He was as interested in us as we were in him. I was a Sikh in a Catholic school; the only boy in a turban. Ronnie made a difficult - as difficult as a middle-class upbringing in the west of Scotland gets - time in my life much easier. What I remember most was his teaching Macbeth and Robert Bolt’s A Man for All Seasons. Certain lines - “Not that I believe, but I believe” - we discussed for ages. I was inspired to go off to study law because of A Man For All Seasons. I wonder if I would have been so eager had I not read the play.

Michael Howard, former Conservative party leader. Mr Rhys at Llanelli grammar school, South Wales

It wasn’t any particular lesson or book that made the impression on me; it was the continuing experience of listening to him and learning from him. He was an inspirational figure. He certainly wouldn’t hesitate to tell you if you had said something stupid. So it was quite a challenging environment, and none the worse for that.

Vinnie Jones, actor and ex footballer, Mr Heasman at Bedmond junior school, Bedmond

The headmaster was a guy called Derek Heasman and he was strong on discipline. He used to have a big white plimsoll with laces and he used to wrap that around my backside most days. One day he phoned my Dad and said, “Look, the boy’s a right problem,” and my old man said to him, “Just get him into sports and football.”

So he put me in the school football team. I was a couple of years too young, but he put me in with all the older boys and a lot of them are still my best mates now. I was fine from then on. He just understood me and my needs and he didn’t judge me.

Mr Heasman was a QPR supporter so the school outing would usually be a game at Queen’s Park Rangers, but he took us to watch England games too. As I got more into football I became quite matey with him - sometimes it’d be me and him playing football against the rest of the class. And as my behaviour improved I got less and less of the slipper.

Ricky Gervais, actor and comedian. Mr Taylor at Ashmead comprehensive school, Reading

Mr Taylor kept an orderly classroom. He didn’t use sarcasm, he played it straight down the line. All he had to do was look at you and you’d stop behaving like an idiot. I had a reputation that I’d cultivated for being funny; it was a rough school and humour was one way around that. In my family, if you couldn’t take a bit of ribbing, you were a pariah. I had three older siblings, so I had to learn fast. And, of course, I carried that into class, even Mr Taylor’s. I’d be the one making funny asides while he talked about Shakespeare. I like to think that Mr Taylor found me funny, but couldn’t laugh because he knew that would be a slippery slope. Maybe he just thought I was a prat.

Emma Thompson, actress. Mr Ray at Beckford primary, Hampstead

On the first day of the school year at Beckford primary we all sat cross-legged on the floor in the school hall waiting to be told which form we’d be going into, and those of us who were lucky enough to be picked to go into Mr Ray’s class cheered. He was a remarkable teacher, and popular with everyone.

Monty Don, gardener and television presenter. Mr Sale at Magdalen College, Cambridge

I got into Magdalen College to read English. I was taught by a wonderful man called Arthur Sale. I was 21 and he was 70, and I adored him. Arthur was a poet, an old-fashioned bohemian from a working-class background in Nottingham. He was funny and iconoclastic. He’d met Eliot and corresponded with DH Lawrence. He seemed to know many leading literary figures, but he never boasted.

Arthur’s standards were astonishingly high. If there was one tiny error of punctuation or grammar, he’d pounce. He wouldn’t allow any sloppiness. I used to sit writing my essays for him with sweat pouring off me. When I read him my work he’d somehow manage to make me feel wonderful, while at the same time telling me that my essay had just scratched the surface and there was much more to learn, a lot of which he would tell me and the rest I would be inspired to go and find out.

Ade Adepitan, paralympian and TV presenter. Miss Singleton at Credon infant school, Upton Park, London

Everyone went swimming, but because of my disability from polio it took me a year to learn. All the other kids learned quickly and I was lagging behind. It was distressing for me because I could see it was down to my disability. Miss Singleton didn’t give up on me. She designed a float that I could tie to my leg to keep it buoyant. Once I could stay up I learned to swim within a couple of months. That is one of my fondest memories of school.

Simon Weston, Falklands veteran. Sergeant Maxey MacDonald at Deepcut army barracks

Sergeant Maxey MacDonald was a short, red-headed Scot in his late twenties, as square as he was tall. He had a great sense of humour, but was a tough character. He had a deep, gravelly voice, a strong accent and shouted words of command like Windsor Davies in It Ain’t Half Hot Mum. He was a cracking bloke, so comfortable with the authority he had that he didn’t need to over-emphasise it.

We were only 16, but we were expected to act like men, wearing uniforms and carrying rifles. Much as our instructors were teaching us to be soldiers - and that means taking life - they were teaching us to stay alive, too. I’ll never forget one particular exercise, when Maxey hit me on the back of the head.

We were on machine-gun drill and I just couldn’t do it right. Your ability with a machine-gun directly affects the safety of your fellow soldiers; if the gun fails, that risks the rest of the guys’ lives. That’s why it was so important I got it right. I understand completely why he whacked me with the machine-gun, but I didn’t appreciate it at the time. He cut the back of my head and said: “You won’t get it wrong again, will you?” And I never did. It was a short, sharp lesson: get it right or people will die. I was a machine-gunner for three years after that.

Karren Brady, managing director of Birmingham City FC. Mrs Peters at Salcombe preparatory school

There was one girl in our class who was always late. Mrs Peters said to her: “If you can make it on time this whole week, you’ll be in for a surprise.” On the Friday, when the girl managed to be on time for the fifth day in a row, Mrs Peters pretended to faint. It was so funny to see your teacher do that. But she had also brought sweets in for everybody to celebrate the girl’s good timekeeping.

I saw her as a special auntie, someone I could talk to and completely trusted. I used to talk about her to my parents, who’d both left school at 16. She’s passed away now, but I tell my children about her because I think it’s important that they find a special teacher. That kind of relationship can have an enormous effect on the rest of their lives.

Interviews by Marged Richards, Pamela Coleman, Judy Parkinson, Sarah Bayliss, Matthew Brown, Harvey McGavin, Rachel Pugh, Michael Shaw, Mark Anstead and David Mattin