Other crime dramas have come and gone, but after 25 years, Taggart is still going strong - in fact, the stars are currently working on their 100th edition.

So just what makes it so successful? Well, that’s a question even the longest-serving cast member, Blythe Duff, struggles to answer.

She says: “It’s a strange thing, because people ask you ‘Why do you think it’s still going on?’, so you feel like you have to justify it. But why does anything work, really? It’s hard to define.

However, she will admit to having a few ideas. The actress, who plays DC Jackie Reid, says: “I think it’s quite to true to the original Taggart - it’s a whodunit and people still know the characters very well. It tries to be quite straightforward in its notions and its ideas, and we all still care about the product.

”We’ve got a great cast and a great crew, so it’s got a lot going for it.”

But while she may be full of praise for her co-stars, Blythe doesn’t think they should take too much credit for shaping the programme. She explains: “There are a lot of times when we think ‘Why don’t do we do that?’ or ‘We should do this’, but that’s not our job.

”Our job is to learn the script, turn up and do it. I think sometimes when people have too much input. that’s when things go slightly wrong.”

Despite this, Blythe admits she does speak out on behalf of her character, especially if she thinks Reid is spending too much time lending her male colleagues a shoulder to cry on, and not getting involved in the action.

She says: “Last year or the year before, I went through that whole comforting era of Jackie Reid. I was tired of that, so I said to the producers ‘I want her to be a wee bit more kick-ass and fiery.”’ Sadly, it backfired slightly. She laughs: “They went a bit overboard. I was actually doing high-karate kicks on people, and thinking ‘Hmmm, okay, maybe somewhere in between, then.”’ Hopefully, the actress will be able to strike a happy balance in this edition, which sees the team find themselves struggling with a sensitive issue when anti-domestic violence campaigner Emily Patrick is murdered.

The detectives discover she had a controversial policy of naming and shaming offenders, which means there is no shortage of suspects.

Convicted rapist Colin McDermott appears to be top of the list, especially as he attended one of Patrick’s lectures on the night of her death, but they can’t understand why the victim didn’t recognise him - or why he identifies her supposedly more moderate colleague June Lamont as the woman who’s been hounding him since his release from prison.

However, things are about to get much more complicated when the cops realise Patrick had also been targeting Kevin Nash, whose caused divisions between Reid and Ross in the past, and looks set to cause emotions to run high once again.

John Michie, Alex Norton, Colin McCredie, Gabriel Quigley, Stephen McCole and Lorraine McIntosh also star.