How we met: Dennis Marks & Michael Frayn

Dennis Marks, 51, was raised in Harrow. A director and producer for almost 30 years, in 1986 he became Head of Music at BBC TV before going to the ENO. He is now managing director of the production company Directors Cut. He has a son and daughter and lives in London with his second wife, Sally Groves, a music publicist

Michael Frayn, 66, was born near London. He was a journalist before becoming a novelist and then a prolific playwright. His latest novel, `Headlong', is shortlisted for this year's Whitbread Prize. He has three daughters from his first marriage and lives in London with his second wife, the biographer and historian Claire Tomalin

DENNIS MARKS: It was 1972 and I was working at the BBC. I was 24 and I'd just started directing my first films. There was a series called Writer's Houses, in which living writers talked about dead ones in the environment of their homes. We decided to do Shandy Hall, Laurence Sterne's house and I asked Michael to write and present the programme.

We actually met in the BBC's offices at Kensington House. I was nervous, partially because I'd admired him so greatly when I read him as a teenager, and also because the gap between somebody of 24 and someone of 40 is a much bigger gap than it is 25 years later. I was expecting somebody who was forbidding, because the writing he did for the papers then was barbed. He looked quite ascetic and severe. In a review of one of our programmes Dennis Potter once described him as looking like a Jesuit who'd just discovered that God is extremely annoyed by prayer! In fact he turned out to be a man of staggering niceness.

We had four days to shoot the film. The weather was glorious and we got through the schedule quickly, which allowed us to walk across the Yorkshire hills, and on our walks we discovered that we shared an enthusiasm for Berlin. About six months later we proposed a documentary special - Michael Frayn's Berlin - to the BBC.

The way Michael works is very collaborative, so we spent a lot of time in each other's company. But during the next film we made Michael's first marriage broke up and the nature of our relationship changed. We talked to each other about our personal lives as well as our interests and professional lives. And when my marriage broke up a few years later, Michael was one of the first people whom I spoke to about it.

Michael is one of the kindest people I've ever met. He is immensely considerate and is very sharp with anybody who is inconsiderate of others in his presence. I once had a row with a producer and was, shall we say, less than tactful in my comments. Michael got very annoyed and ticked me off roundly - quite rightly too.

The thing I admire most about him is his extraordinary skill at communicating incredibly difficult ideas. He has a way of using humour to open doors into some of the deepest and most problematic areas of life. He also has a gift of finding something resonant and poetic in the ordinary that's specific to him.

We are both control freaks in our different ways and Michael is incredibly stubborn. We try to be very polite control freaks, but basically we want life to go according to plan and we organise things meticulously. Almost everything Michael's ever written has been about the complete impossibility of achieving this.

Looking back I can't work out how I had the nerve to do the Berlin film, given how inexperienced I was. I rather hoped that Michael wouldn't find me out. Well, maybe he did find me out and was just too polite and courteous to let me know, but somehow we got through it, and the end result is that we're very good friends.

MICHAEL FRAYN: I got a message that this young director wanted to make a film about Laurence Sterne's house. Since I greatly admired Sterne I arranged to meet him and we got on quite well and had congenial ideas and so we made this short film together.

Dennis seemed enormously young. He had this great beard like an Old Testament prophet, but he was fresh out of university at the time, and he did very well, most ingeniously. He was enormously bumptious and I was absolutely amazed by his sheer aplomb, at his being absolutely at home in the world and knowing how everything worked in a way that I just didn't.

He's very bright, and this was evident from the very first moment. Like me, he liked all the postmodernism in Sterne, and we found ways of suggesting Sterne's style in the style of the film.

The shoot was nice. It was early in the year and the air was very nippy. There was one bad moment when a lamp caught fire and we almost destroyed the house, which would have been the first time the writer's house had actually been destroyed in the making of the film.

While we were making it we discovered we had a mutual passion for Berlin. Dennis said he'd long wanted to make a film about Berlin and I had too, and we went on to make this film, a much longer enterprise, and I have to say I still feel rather proud of it.

We've done about six films together over the years, and that does involve a lot of time spent in each other's company. During every film Dennis and I have made together, we've had an absolutely colossal row at some point, but we always make it up again afterwards. He is quite an abrasive personality and has very strong views. I've got views as strong as his, and I mostly give way on everything, but we do occasionally clash.

One of the things I've done with Dennis, which I've never done with anyone else, is to show him the first drafts of my scripts. He is extremely clever in seeing what lies behind them and the ways in which they might be turned into something visual.

Dennis saw a lot of the break-up of my first marriage, and we talked about it. As a result he confided in me when his marriage broke up. We both have second wives and we all get on extremely well and often the four of us have dinner together.

Dennis has great loyalty to his friends, and great warmth. He can be extremely sympathetic and sensitive. He can sometimes be less so. He's very interesting and he's very widely read, much better read than I am, and much better informed about ideas.

When I first knew him I thought we were from different generations. He was very much a young radical at the time: a terrific union man at the BBC, always embroiled in office politics in a way that that generation was. I always used to think of him as being extremely young. I think he's caught up a bit now. He looks a more respectable age.