It used to be that, whenever film and television drama required a drunk, the casting director reached for a copy of Equity's Scottish directory. Somehow the part of the belligerent, alcoholic down-and-out was never quite complete without a broad Glaswegian accent. The words "typing" and "stereo" spring to mind (though not necessarily in that order).

This may well have been bad news for our national image, but it was certainly good news for a generation of Scottish actors if, for no other reason, than it kept them in regular employment well beyond their official sell-by date.

Sometimes it was even worse. Because sometimes, in the absence of a Scots actor, they'd get an Englishman or an Irishman to play the whisky-swilling fool in a cod "See-you-Jimmy" voice.

But that was then. The good news is that times have changed. In these days of political correctness, the drunken bum has become an equal opportunity role and can just as easily be portrayed by a Scouser, a Geordie, a Yorkshireman, or even an upper-class Home Counties toff.

The bad news is that, apparently, those crafty casting directors have found another use for Scotland's thespian community.

If a public rant which started on Radio Clyde's Breakfast With Bowie show is anything to go by, then Scots viewers are becoming increasingly annoyed at the way we're being portrayed on the television screen these days. Now it's not the drink that's the problem; it's our violent and psychopathic behaviour.

According to the programme's producer, Sara Prockter, the station has been bombarded with calls bemoaning the fact that members of our mild-mannered acting fraternity are fast becoming ubiquitous as the token baddies in TV dramas.

"It all started when one of our listeners phoned in to complain about the way Scottish people were being played in soaps these days. And it just started the ball rolling. We've been getting loads of emails and text messages," she says.

"They've been on about Scots in EastEnders and in Brookside. And every time a Scots actor appears in The Bill you say to yourself 'Well, that'll be our villain this week,'" she adds.

George Bowie, the programme's presenter, says: "I hadn't really thought about it until the subject was brought up, but it's true. And it seems to have struck a real chord with our audience. I can't remember when we had a greater response to anything."

The listeners' blue touch paper appears to have been lit by a particularly nasty character called Trevor, a psycho barman and habitual wifebeater from EastEnders (played by Alex Ferns). But is he really just the latest in an ever-lengthening list of villains from the north side of Hadrian's Wall?

Well, apart from the notable exceptions of Gerard Kelly (who was famously cast against type as a gang leader in Brookside) and Forbes Masson (who played a child-molesting teacher for a while in EastEnders) you'd be hard pressed to think of any other Scottish villains fit to hiss in TV's soaps. And as for The Bill? Well, surely any over-subscription in the Scottish villains' department is offset by the constant presence of that cuddly Glaswegian, DC Lennox.

To be honest, you'd have to rack your brains to put a kilt on any memorable telly bad guys, whether soap or straight drama, of recent years. You really have to go back to the days of The Sweeney in the seventies to find a series which regularly featured Scottish hardmen (usually alighting from the InterCity overnight sleeper at Euston, sawn-off shotgun in their grip, to carry out a swift bank job before heading back on the 17.15 to Glasgow).

You disagree? Fine, but consider the list of Scotland's leading actors. Sean Connery? Never played a real baddie in his puff (though he did come perilously close as the stressed-out detective in Sidney Lumet's The Offence). The same goes for Ewan McGregor. Robert Carlyle? Okay, there was Begbie in Trainspotting and the follically challenged terrorist Renard in The World Is Not Enough, but those were just two examples from a long and distinguished list of acting credits.

Billy Connolly then? Brilliant as the nasty piece of gangster work in The Debt Collector but more familiar, surely, for his portrayal of the widowed Queen Victoria's main squeeze in Mrs Brown.

Dougray Scott? Granted, a villain in Mission Impossible 2 (and an even better one in the Wales-set thriller Twin Town) but much better known these days as a big screen hero.

I could go on. Robbie Coltrane, John Hannah, Dougie Henshall, Peter Mullan, James Cosmo . . . all of them great actors, but not exactly renowned as major, heavy-duty bad guys.

Ah, you might say, you haven't yet mentioned David Hayman. Now there's a man, surely, who's not averse to a spot of on-screen villainy. Sorry but, all things considered, wrong. There was, of course, his brilliant portrayal of Larry Winters in 1989's Silent Scream. But after that, you're struggling to present a track record of bad-guy roles.

Hayman, by the way, agrees that the list of Scottish telly baddies is a very short one. "Apart from Gerard Kelly in Brookside and the new guy in EastEnders, I don't think I can recall any off the top of my head," he says.

In terms of movies, he goes on: "The thing is that rarely do you get any actors actually playing Scottish roles in big films. So, inevitably, you get even fewer Scottish villains.

"I suppose that, rather than bad guys, the public perception of Scots is as tough guys. A lot of that has to do with the Glaswegian accent. It's like the character I played in Lynda La Plante's Trial and Retribution series and, I suspect, Alex Norton's new detective character in Taggart. They're not bad, they're just tough."

Hayman is 100% correct. Scots actors do hard-but-fair particularly well. From television, the late Mark McManus was the perfect example as Taggart and John Hannah, as Rebus, is keeping the flame alive.

But playing the mean man? Scots actors should be so lucky. Their English counterparts, stars such as Jonathan Pryce, Tim Roth, Gary Oldman, and Alan Rickman, are helping to keep British Airways (barely) afloat by regularly shuttling between London and Los Angeles to play villains in Hollywood blockbusters. But only perhaps Brian Cox - a splendid villain when he sets his mind to it (he was the original Hannibal Lecter, after all) - is carrying the saltire for Scotland across the Atlantic.

Still, let's end with two examples of genuine, 24-carat Scottish bad guys which may, with the passage of time, just have escaped your memory. First, Angus Lennie as the wee chef in Crossroads (though in his case it was the performance rather than the character which was criminal).

And second, Iain Cuthbertson as Charlie Endell in Budgie. Now there was a bad guy so good that he's up there at the top of the TV villains' list.