With a script that called upon him to yell “Get your trousers on, you’re nicked”, with an air of both authority and menace, there was only ever one choice to play the 21st century Jack Regan.

Ray Winstone has been on a path that would lead to him becoming head of the “Todd” at the “Sweeney” since he made his TV debut as an extra on the original show, 35 years ago.

Back then he was a “good looking geezer” who kept talking while stars John Thaw and Dennis Waterman were trying to say their lines in an attempt to get his fee increased.

Ray knew he had iconic shoes to fill in taking this role, so he didn’t even try to copy the late Thaw.

“He was a fantastic actor. That was one of the things about doing this, how do you follow that? How do you make it better or even as good? And you can’t. It’s impossible. So you have to reinvent it and make it your own.”

Ray was lucky enough to work with John Thaw on a number of other occasions, and came to appreciate his tolerance when he nearly wrecked a day of filming on Kavanagh QC.

“I was rehearsing Nil By Mouth (the Gary Oldman directed project in which he played an abusive husband), I was doing a play at the Royal Court and I had a really bad day on Kavanagh,

“I had this 15-minute scene and I couldn’t remember a line. As they said ‘action’ I forgot it. My brain had switched off. It was my body’s way of saying ‘I’ve had enough’. I remember the extras thanking me at the end of the day for giving them another four hours on set that they’d get paid for,” he recalls ruefully.

“It was a confidence killer but John Thaw was terrific about it and the next day I came back and I was right as ninepence. It was probably one of the best scenes I’ve ever done as an actor.”

He also dismissed other actor’s accusations that Thaw could be unsociable.

“He had so much dialogue to learn, he’d go to his Winnebago. That’s what happens when you carry a show like that, on your shoulders, you have to lock yourself away. He was a complete and utter professional.

“I kind of learnt something from him about being humane about things, and giving people time. He was a very special man.”

Though TV’s The Sweeney may seem hopelessly outdated these days with its flared trousers, kipper ties and bloke-ish attitudes, back in the 70s it was groundbreaking stuff that redefined police series.

“You had Dixon of Dock Green and Softly, Softly, which were great in their own right, but this was the first show on TV that was down and dirty,” says Ray. “Round where I lived we could all kind of relate to it in a way. It was real.

“Now, you have shows like The Wire in America and HBO stuff that are making kind of the same sort of stuff. It may be updated but it all kind of, for me, came from The Sweeney.”

One significant change in the past 40 years is that woman detectives help make up the Sweeney team and are just as likely to be the ones firing guns or swinging baseball bats to take down the criminals.

However, Regan’s womanising ways are unaltered, which sees him embroiled in an affair with a married flying squad member (Hayley Atwell). The result is some rather disturbing love scenes (given that there is a 25 year age gap between the two) including a hasty coupling in a toilet and an assignation in an hotel rather ruined by Ray’s decision to wear some unflattering underwear.

“I’ve got a bit of advice for you: don’t wear yellow boxers when you’re in a sweaty room all day, alright?” he says with a grimace.

He is fully aware that as a middle-aged man and a stranger to salads, he doesn’t cut as buff a figure as his co-stars Ben Drew or Damian Lewis, yet he is the one who has to convince an audience he could woo a woman played by an actress who was once the beauteous Julia Flyte.

“I don’t know what is appealing to women, I’m a 55-year old fat man,” he shrugs.

“I think what makes a man sexy is the way he treats women. You got to be genuine, a gentleman, and a little bit of a rogue at the same time but if you try and set out to be that you’re probably not going to achieve it.

“I don’t know how that works, ask the ladies, I haven’t got a clue.

“But if I am (a sex symbol) fantastic, I love every minute of it.”

Considering its relatively tiny budget (it cost just £3 million yet squeezes in some glamorous London locations, a shoot out in Trafalgar Square and an epic car chase filmed by the Top Gear team) The Sweeney is quite an accomplished piece of British movie-making.

If the box office returns are healthy enough, there could be a convincing argument for a sequel. Ray says that he is certainly game.

“I’d jump at the chance, without a shadow of a doubt. Turning up to work on this every day was an absolute pleasure and that comes from the top. It comes from your director and your first assistant, right the way through the cast.

“I’ll have it every day of the week and twice on Sunday. But don’t hold me to that because I like my Sunday dinner!”