Would they be interested in doing some teaching trade secrets for this new channel? Not really. They had tried to do a teaching episode for the original series and phoned every school in the West Midlands. Not one teacher would appear in the programme and on many occasions the phone was slammed down.

“That’s what teachers are like,” they informed me. That was eight years ago. They somewhat reluctantly agreed to give it another go in the summer of 2003. They were gobsmacked to discover that virtually every teacher they contacted was dead keen to be on telly.

The truth is that, until very recently, TV producers have, on the whole, given the teaching profession a wide berth. Do a rough count of dramas and documentaries devoted to the professions and you will find that teachers come very low down the list - well below antique dealers and roughly on a par with undertakers.

Everyone has been to school, and therefore has powerful opinions about education, so producers ought to have been falling over themselves to pitch ideas for programmes about teachers and schools. The trouble was that for many years they were looking for the real life Bernard Hedges, the well-meaning NQT (as we would call him now) played by John Alderton in the popular sitcom Please Sir. But, of course, Bernard did not exist. Instead, producers found us a surly bunch: deeply suspicious and certain that they were going stitch us up.

Teaching in London’s Hackney in the early 1970s, I was one of them. It’s true we were a bit paranoid. We knew there were political forces out there itching to find evidence of slack discipline and the erosion of standards.

So when, from time to time, we did receive a call from a well-intentioned documentary producer, we played hard to get. The hapless TV researcher knew that even if she did get past first base, there was going to be endless talk about the dreadful inconvenience of filming, the need to secure written permission from absolutely everyone and then, when the schedule is in place and the crew arrive, the union rep will have called an emergency meeting to challenge the terms of the release form.

But about five years ago something changed. Suddenly, programmes about teachers, if not all the rage, were at least getting a more sympathetic hearing from channel controllers. I date this change from the Channel Four drama series Teachers. This was a series that the education establishment wanted to ban, and yet it seemed that the then Teacher Training Agency was seriously considering sponsoring the second series. Apparently, applications to the profession had leapt up as a direct result of the series. Hot news! Teachers were not paranoid ideological purists but flawed human beings interested in sex and skiving. In the age of Big Brother, these were just the sort of people that TV producers could do business with.

At the same time, real teachers were changing too. Now that Chris Woodhead, former chief inspector of schools, had moved on, there were green shoots of confidence in the staffroom. Forward-looking heads, competing in the educational marketplace, could also see the benefits of a bit of air time.

So, to their surprise, TV producers - and by this time I was one of them - found their calls were being returned. Some schools even had a deputy head in charge of press and publicity, ready to talk location fees and DVD rights.

A few years later and Janet Street-Porter was taking a primary class under the willing supervision of real teachers who were happy to play their part in a celebrity format. Then, before you know it, Phil Beadle, who on his own admission was very surly when approached, is in The Unteachables getting kids to read poetry to cows and dealing manfully with the resulting celebrity status. Forgive me if I remind you that teachers have leapt ahead of those cops and medics. They are the only profession to have their own TV channel. At the last count, more than 5,000 of them had been filmed with barely a cross word and the producers just love them.

Andrew Bethell is director of programmes at Teachers’ TV