BRADFORD actor Peter Firth reprises his role as MI5 chief Harry Pearce in a big-screen version of spy drama Spooks.

With many major characters killed off during the ten series of BBC1's Spooks, Pearce, head of the counter terrorism department at MI5, was fortunate to still be standing by the end.

Now Peter Firth, 61, stars in new film Spooks: The Greater Good, alongside Game of Thrones heart-throb Kit Harington.

Born in Bradford, Mr Firth was a child actor in the 1970s, starring in TV shows such as Here Come the Double Deckers. As a teenager he starred in a National Theatre production of Equus, in London and on Broadway

He has appeared in TV dramas such as Rome, American drama Law and Order and the 2011 re-make of South Riding, filmed in Bradford, and his films include Letter to Brezhnev, The Hunt for Red October and Roman Polanski's Tess.

Mr Firth thinks the danger element of Spooks, with nobody being safe, played a key part in the success of the Bafta-winning series.

"It had never been done in television. Nobody had ever had the idea of establishing heroes, then killing them off on a regular basis," he said.

"When we did in the second episode with Lisa Faulkner, plunging her head into a deep-fat fryer, the reaction was so extraordinary, it became clear this was a powerful dramatic tool. For the viewers it meant all bets were off. If you had an investment in a character and they were in trouble - they were really in trouble. That led to people being fascinated by the show."

The drama came to an explosive end in 2011, with Harry still in charge of the team, dubbed 'The Grid'. Mr Firth said the film was a "natural progression".

"The scale of the series was much bigger than normal TV drama, it always had aspirations to make it to the big screen. We took the DNA of the TV show and just put it in a bigger frame, with better, more exotic locations, more fabulous stars," he said.

Fans can expect explosions and heart-in-your-mouth chases, but no over-the-top CGI effects. Mr Firth describes it as "believable, but still cinematic and sexy".

"Filming on location in London, we didn't have any control over the streets so we'd hide cameras on rooftops and in windows and I'd be hooked up with sound, which looked like part of the spy equipment anyway.

"We'd film in busy streets, with people completely unaware we were doing that. It's a great way to work, quite exciting."

* Spooks: The Greater Good is released in cinemas tomorrow.