Can Spooks compete with Bond on the big screen?
When it first aired more than a decade ago, the BBC TV spy series Spooks was groundbreaking.
It boasted fast-paced, slickly-cut action; terrorist plots that were sometimes uncannily close to real-life events; and a cast playing MI5 agents who often met grotesque ends.
The death of Lisa Faulkner's character Helen Flynn in a chip pan fryer was the most complained-about TV moment of 2002.
Three years after the series ended in 2011, Spooks: The Greater Good is finally a spin-off movie, made by the TV show's original director, Bharat Nalluri, and starring Game of Thrones' Kit Harington.
But with the Bourne and Bond franchises reinvigorating the spy thriller genre, the question has to be asked: why now?
"We were in development for 10 years," apologises Peter Firth, one of the original stars of the TV show, who plays agent Harry Pearce.
"They speak in the film industry of development hell, and I can tell you it does exist. I'm sorry we took so long. It always felt like a film was trying to get out of the television.
"Having finished the TV show three years ago, there is a time imperative of trying to hang on to your fans. In this case, I think we've made it just in time."
Firth, who once again takes the leading role, calls the film "a natural progression".
"We've taken the DNA of the TV show and put it in a much bigger frame. We used to do the TV show on a low budget, and now we've done the same thing on a big budget. That's what it needed."
Kit Harington joins the film as the latest in a line of "spooks" that have included such actors as Richard Armitage, Matthew Macfayden, Keeley Hawes, Hermione Norris and David Oyelowo.
Harington, who was 16 when the TV series first aired, describes himself as "growing up with it".
"It aired just after 11 September occurred and, in a way, was a reaction to it," he says.
"It was a very important TV show. The director didn't want me to watch a lot of back episodes, so I didn't. He wanted me fresh for it."
Nalluri says one of the biggest challenges in making the film was not being able to change Harington's hair. The actor is contractually obliged by HBO to retain his Game of Thrones character Jon Snow's haircut.
But the difference between Spooks and Game of Thrones, Harington says, was "a big part of why I wanted to do the film.
"Running around with a gun, doing high-octane stunts, living as a modern man in the UK - it was very appealing to me.
"My character, Will Holloway, thinks very analytically, and I'm not used to playing men like that. Spooks is very bleak, it's also very grey - you never know who the good person is.
"One thing Spooks and Thrones do share, though, is they kill people off fairly regularly, and pretty realistically. I think Spooks utilises the potential death rate in a spy thriller very well."
At its height, Spooks (also known in some countries as MI5) was shown in more than 60 countries.
With a supporting cast that includes Tim McInnerny, Jennifer Ehle and Homeland's David Harewood, Firth is optimistic that the film will have an audience.
"Kit brings a whole Game of Thrones audience with him, and it's a young audience. I have an audience of old ladies who live with cats. Between us we must be able to muster a draw!
"Expectations are higher, though. There are people in suits lurking around mysteriously in the shadows, and with film, they're people at the top of their game.
"We also had a definite script that we never had with the TV show. We were keeping it on the hoof in the TV show to try and keep abreast of what was happening in current affairs.
"If you can dramatise a news story, you can dramatise what's happening behind a news story. That's fascinating for an audience and I think that was part of the appeal of the TV show."
Firth stresses that the film's plot is also current - showing London under threat from home-grown Jihadism.
"In a couple of instances, Spooks predicted actual news events," he says. "We'd already shot an episode that was due to air two weeks after the 7/7 bombings, about a London tube bombing at King's Cross.
"We did show it, but we had completely re-formatted it and made it more palatable. It was just too near the knuckle.
"But that does give you an indication of the cleverness of the minds that work on Spooks - analysts looking at what might happen and then dramatising it."
That, he continues, is what makes Spooks different to both Bourne and Bond. "They're rooted in fantasy, although perhaps Bourne has a toe in reality.
"We know we can't compete with them. Also, they are set all over the world [and] we are very definitely British, and looking outwards. This was filmed all over the UK. I think, ultimately, we want Spooks to be believable."
While Harington admits "he'd love to have a go at Bond one day - who wouldn't?", Firth hopes he won't lose his latest recruit just yet.
"Whether we make another Spooks movie hinges on one thing only, and that's just business," he says.
"If it does well and people like it, we have loads of material to provide them with follow-ups."
Spooks: The Greater Good is out on 8 May.