The same is true if you mention Up the Junction, G F Newman's Law and Order or any of the other milestones of British television drama Mr Garnett has produced. 'Nostalgia is the British disease,' he says contemptuously. 'Too many people sit moaning about the present and inventing a past that never existed. There never was a Golden Age of British television. This nostalgia is one long Hovis ad and I won't take part in it.'
In vain to argue that these past glories deal in anything but nostalgia. Cathy, in 1966, almost singlehandedly changed government policy towards homelessness, at least until Mrs Thatcher came along. Up the Junction, his pioneeringly sexy Wednesday Play from 1965, was attacked only the other week in the Daily Mail as being the chief culprit in the supposed Sixties undermining of Britain's moral fibre. G F Newman's quartet of plays about the corruption of the police caused pandemonium in 1978.
Tony Garnett's sole interest, he says, is the present. The political dissident of the Sixties and Seventies is now the 57-year-old chairman of Island World, an independent production company backed by Chris Blackwell, former boss of Island Records. He can make only what his customers - BBC or ITV - want to buy, and it is a tough market. British television today, he says, is 'like Hollywood without the money'. But as in Hollywood, where he spent 10 years producing movies, he clearly enjoys working the system.
'You have to deal with the world as it is,' he says. 'It was the politicians that made these structural changes. The people who work in television have to make the best of them. Just as in the Sixties I was having to do a lot of infighting with the BBC management to get things on, now I have to fight in a commercial environment.'
Over the past two years, Island World has achieved the nearly impossible. It has produced a police series that's different. Between the Lines, which recently returned for its second series on BBC 1 on Tuesdays at 9.30, has been up to the minute and avoided almost every cliche that has made cop drama the most predictable of all popular television audience fodder.
Between the Lines is not about Flying Squad roughnecks chasing cars through the East End or introspective inspectors solving one case per month in provincial cities. It's mostly not about the police as good guys at all, but as mortal, fallible people under great pressure.
Given Mr Garnett's reputation for being at the cutting edge of television drama, it seems paradoxical that he should have wished to make yet another police series. But, he insists, it's a natural television genre. And since the central character, Tony Clark (played by Neil Pearson), is an officer in the Complaints Investigation Bureau, he believes the series is 'a piece for the times'.
'The police know that in recent years they've lost the confidence even of the middle class,' he says. 'Any intelligent senior cop - and most of them now are very intelligent - knows you can't police a country without the consent of the people. They're very concerned to get back the confidence of the public. So we're looking at the problems which concern both them and the citizen every week.'
Tony Garnett is wary of talking to journalists. This stems from the Seventies, when each paper he opened had a different story about which left-wing political faction he belonged to: 'None of them true; I've never joined a political party in my life.'
Born in Birmingham into a family he describes as 'labour aristocracy', he won a state scholarship to London University but spent most of his time acting, a career he abandoned in his late twenties to become script editor, then producer, of the BBC's Wednesday Play. It was here he forged his famous partnership with the director Ken Loach and their pioneering brand of social realism. Much of that work, he says, was fuelled by anger at the waste of young lives he saw around him. 'When I was very young I thought we could make a film and change the world,' he says. 'But there's a lot more homeless now than when we made Cathy. The only positive result of that film, as far as I can see, is that the people who made it now live in very nice houses.'
He bristles a little when asked how someone of his left-wing views can have moved to Hollywood with such palpable enjoyment. But after a decade producing a mixture of American films, from Sesame Street's Follow That Bird to the atomic drama Fat Man and Little Boy, he came back to Britain to be with his 14-year-old son, who lives with him half the week. 'I want to be there when he gets home from school, which is why I'm not doing any movies for the time being.'
Island World has produced two well-received Screen One films for the BBC - the football drama Born Kicking and Wide-Eyed and Legless, with Julie Walters. In production for BBC serials is Cardiac Arrest, a black comedy about the health service, written by an NHS doctor.
The BBC is also trying to persuade Tony Garnett, the writer J C Wilsher and the producer Peter Norris to make a third series of Between the Lines. Original, adventurous television though it might be - and the recipient of three best series awards last year - the programme does not draw a huge audience. Story-lines have become distinctly more accessible, but it's still being watched by around 7 million viewers, compared with 10 million for ITV's new crime series, Cracker.
Mr Garnett says the BBC has put no pressure on him to improve the ratings, but admits that in today's competitive climate making risk- taking programmes is becoming increasingly hard. 'There's a commercial imperative now that says you must get the ratings,' he says. 'That's not entirely bad, but it does make things more difficult.
'There are fewer people who can say yes to a project now than at any time in my working life. British television is getting more like Hollywood, where there are lots of executives who can say no but only one or two who can say yes.'
Can good drama survive? 'It will survive in some form because for thousands of years people have liked to be told stories. What it will be like? I don't know. All we can do is have a go.'