As a parent myself, I’ve been trying to get an indication of what a good teacher is and I think the best are the ones where you don’t know you’re being taught. At 13 and 14 you spend more time with your teachers than you do your parents, and Ronnie undoubtedly brought out the best in me.

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.

I put his slightly rounded shoulders down to his being an exam board marker. We watched his straggly brown hair imperceptibly turn grey. He’d taken to growing a long, untended, avuncular beard, which really suited him. He was very much involved in justice and peace: Catholic schools have a big thing about those two. For all their faults, the Catholics, bless them, have all the guilt, and therefore, to assuage guilt, a social conscience.

Ronnie was a renegade, a firm believer in the role of the individual within society. He always walked around the classroom as he spoke. He encouraged lively debate and never told us what to think. You found yourself at the end of a lesson thinking: “How have we gone on to abortion? I thought we were talking about Macbeth.” You felt very educated at the end of it.

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. There were a million things to read at home, but not those plays. My father was a maths teacher and a lot of the literature was there by default rather than design. The most memorable part of learning Macbeth was when Ronnie explained that Macbeth inherently wasn’t a bad man. He also taught me the word mutability.

One overwhelmingly powerful memory about being a pupil of Ronnie Renton was that the whole class felt inspired by him; you weren’t the only one. What Ronnie did for a generation of pupils was give them confidence. Cliched as it sounds, he taught us to fish instead of giving us fish, so we grew up with an ability to think for ourselves. He must have heard our opinions before but acted as if it was the first time.

A couple of years ago I met Ronnie in Glasgow, 20 years after I’d last seen him. There’s a street called Ashton Lane where I did most of my growing up.

Ronnie Renton turned the corner and I just hugged him. I’m a big, grown man and I hugged him and started crying. I guess I was saying: “You gave me so much.” He’s still at St Aloysius, now deputy headmaster. If I could be half the man he is, I’d have achieved a great deal.

Writer and comedian Hardeep Singh Kohli was talking to Marged Richards

The story so far

1969 Born in Acton, London

1974-77 Meadowburn primary, Glasgow

1977-86 St Aloysius Jesuit school, Glasgow

1986-89 Glasgow University law school

1990 Graduate production trainee, BBC

1992 Moves to London to direct BBC children’s television

1999 First short film, The Drop. Winner of the Audience Award at the Bradford International Film Festival

2003 Writes and presents one-off Bafta-winning documentary In Search of the Tartan Turban

2005 Writes, directs and stars in Meet The Magoons (Channel 4)

September 19, 2005 Presents Hardeep Does ... on Channel 4 every day for a week at 9.30am