Cheerio, pal! ITV turns its back on Taggart

I was sitting in the audience at a 60-seat fringe theatre in Victoria, a bolt-shaped building almost hidden beneath a flyover, watching the first musical I had ever written. I based it on the notorious Cleveland Street scandal of 1889, a colourful affair involving a male brothel, telegraph messenger boys and Queen Victoria's grandson, Prince Eddy, who reputedly visited the "house of iniquity". Why a musical? I'd never written one before, and I'm a great believer in trying everything.

It was no ordinary evening. I'd heard only an hour before that the Network Centre had axed Taggart after 28 years. Twenty-eight years? Where had that time gone? For half my lifetime, the dour Scottish detective – first in the incarnation of the unforgettable Mark McManus and later the marvellous Alex Norton – had trodden the mean streets of Glasgow to that familiar theme tune, solving gory crimes, barking at his colleagues, and generally giving Glasgow its reputation – totally undeserved – as the murder capital of the world. Or perhaps one should say "murrrder". The catch-phrase needs no repeating here. Like Queen Victoria's "We are not amused", I don't believe anybody ever actually said: "There's been a murder." But there, I repeated it. I've never been able to get away from it.

Taggart was a first for me too, just like Cleveland Street. I was a young playwright, working on the London fringe, when Robert Love, the head of drama at Scottish Television, gave me my first opportunity to pen a television play. Those were the days when faceless committees and management consultants and advertisers didn't hold sway over programme content or style. After writing three short TV plays, Robert asked if I would write a whodunnit about a Glasgow detective. That talk took place in the incongruous environment of a Covent Garden tea shop.

A whodunnit about a Glasgow detective? I had never written a murder mystery. I was an Edinburgh ex-public schoolboy who often felt ashamed to open my mouth in a Glasgow pub for fear of attracting unwanted attention. The two cities may be only forty miles apart, but the social and cultural gulf feels like 400 miles. But I took up the challenge. After reading close to 30 Agatha Christies to learn the technique, I launched into my first TV murder story, a marathon three hours in serial format. It fell apart and unravelled by the end of the second episode. I remember weeping in despair. I recall Robert suggesting I go back to the beginning and start again. And this time, he said, work out the ending first. Know who did it. And then you can confuse and confound the viewer – not yourself.

It seemed simple and pretty obvious advice. But it worked. And the result was "Killer", which a year later became Taggart. Mark McManus was my choice from the beginning, and I was thrilled when I learned he wanted to do it. As series followed series, he made the character his own, so much so that sometimes a line of dialogue or even a whole speech would become unnecessary. Mark McManus, like the Gorgon of mythology, could turn his colleagues to stone with just a look.

I adopted the attitude that each show would be the last, that they surely wouldn't commission another. That way you get no unpleasant surprises. But it kept on going, and my plots got wilder and wilder. I felt like a child in a play pen with few bars. I was reading real-life crime by this time, immersing myself in true stories about unusual murders, twisted motives and how killers are usually caught not by ingenious detectives but by stupid mistakes. Taggart became known for its bizarre plots and gruesome murders (my favourite was "Nest of Vipers" in which deadly snakes were the murder weapon) but all of them had some grounding in reality. Maybe the venomous spider at the Burns Supper was a bit cheesy, but it was great fun, and Taggart was always about fun.

When Mark McManus died, it was like a body blow, though his death was not unexpected. I was on holiday in New York at the time. A call from Scottish Television advised me not to say anything to the media. They were carrying on with the series. It was still going to be called Taggart. By now, they said, it was a trade name, and audiences recognised it as signalling a particular kind of show.

I mean no disrespect to Mark McManus when I say that a couple of my favourite stories were written after his demise. "Out of Bounds" took us into the hot-house atmosphere of a Scottish public school in a story about bullying, revenge and murder, and "Angel Eyes" dealt with the search for a gay serial killer. It was a first when we "outed" one of our regular characters.

When Robert Love left Scottish Television in the late 1990s, I decided it was time I moved on from Taggart too. When it began, the programme was shown over three weeks in serial format, though we also filmed a number of two-hour Christmas specials. Lately, it has been reduced to just storylines of one hour which, if you take away the commercials, leaves about 46 minutes to tell the story and wrap up the mystery. It is almost as though audiences are no longer credited with an attention span. Maybe now there is simply too much on the box. But its legacy remains – it has become the longest running television detective series in the world.

An opportunity to produce my own show at the Edinburgh Festival in 2008 was a welcome return to theatre, but another first in that I'd always wanted to "do Edinburgh". I don't suppose you achieve anything in life unless you tell yourself you can do something you've never done before. Hence my musical on the Cleveland Street scandal.

But Taggart will always stay close to my heart. I cried when I heard the news, not out of sadness, but because it had been so much part of my life.

I can hear Mark McManus in that gravelly voice of his calling me a "big softie" and telling me to just get on with the job.

The facts of the case...

* It first aired in 1983 – and the first storyline, "Killer", won a Scottish Bafta.

* A host of actors have made cameo appearances in the series over the years, many of whom have now gone on to Hollywood success, including Jason Isaacs, John Hannah, Ewen Bremner, Alan Cumming and Ashley Jensen.

* Though the exact number of murders in the series remains a mystery, it is estimated there have been more than 450 since it began.

* ITV's decision to cancel the show after 28 years and 109 storylines was due to what the broadcaster considered disappointing ratings, averaging 2.5 million viewers per episode. It was attracting up to 14 million in 1983.

* Glenn Chandler, the creator of the series, lifted the names of characters from the show from gravestones in Glasgow's Maryhill cemetery.

* Mark McManus who originally played Detective Chief Inspector Jim Taggart, had appeared alongside Mick Jagger in the 1970 film Ned Kelly.

* McManus died on set from pneumonia in 1994, in the middle of filming an episode. His absence was explained away by his having constant meetings with the Chief Constable.

* Taggart has its own fan convention. The first took place in 2005 in Glasgow, of course.

* It is sold to 56 countries across the world, including Afghanistan, Taiwan, Mexico and Papua New Guinea.

* The number of times the phrase "There's been a murder!" has been uttered in the show is? Zero, apparently. It's a myth.