The BBC’s long-running spy thriller series Spooks (aka MI-5 in the US) came to a close a few years ago, and instantly sparked rumours of a big-screen continuation. Unlike most such rumours, that one actually came to fruition: this result hit UK cinemas in the summer, and is now making its way across the pond — under that Mission: Impossible-esque title, of course.

The TV series is probably best remembered for the way it regularly killed off its leading characters in shocking fashion, thanks to the most infamous of them all: the “deep fat fryer incident” from the second-ever episode. It was about a lot more than that, though. Beginning in 2002 in the wake of 9/11, a series about the security service defending the country from terrorism couldn’t avoid being ultra-relevant, and it ran for a decade during which such issues never ceased to be pertinent (and haven’t since). That other famous British spy institution, James Bond, was at the tail-end of the Brosnan era when Spooks began, and the lower-key TV series was — like Tinker Tailor and others before it — pitched as a “real world” version of what the security services got up to. Storylines were “ripped from the headlines”, often with eerie prescience: after one early episode, the series’ lack of end credits led some viewers to believe the real BBC News bulletin that followed was still part of the drama.

Early seasons focused at least as much on things like the mundanity of spycraft, or how one went about having a personal life while also being a sometimes-undercover agent, as they did on the exciting action of counterespionage — as evoked in the memorable tagline “MI5 not 9 to 5”, of course. As the years rolled on, things got increasingly outlandish and grandiose, just as almost every spy series that starts out “grounded” is wont to do. In season three, an entire episode was spent on the moral dilemma of whether it was acceptable to assassinate someone; a couple of years later, assassinations would just be a halfway-through-an-episode plot development. The one constant through all this was section chief Harry Pearce (Peter Firth), the M figure to a rotating roster of “James Bond”s, including Matthew “Ripper Street” Macfadyen and Rupert “Whitechapel” Penry-Jones, as well as other actors who didn’t go on to lead Jack the Ripper-derived crime series, like Richard “The Hobbit” Armitage.

Now, a couple of years since the TV series wrapped up its ten-year run, Spooks has attempted to make the leap to the big screen. Although they’ve roped in the fella who directed the first-ever episodes, the screenwriters are the final two seasons’ showrunners, so the movie follows on from where the series ended up rather than re-establishing itself in where it all began. What does that mean in practice? Sub-Bourne action in a film that often appears more like a well-budgeted TV movie than a proper feature film.

But I’m getting ahead of myself. The story begins with Harry running an op that goes wrong, during which terrorist Adam Qasim (Elyes Gabel) is sprung from custody just before being handed over to the CIA. Cue international incident. Naturally the blame is pinned on Harry, who consequently throws himself off a bridge. Except no one buys that, so they drag in Will Holloway (Kit Harington), a disenchanted one-time protégé of Harry’s (i.e. the series’ latest “younger man who can do the running around”). He knows nothing about it (obviously), but they want him to track Harry down nonetheless. Turns out Harry suspects there’s a mole in MI5 (because it’s a spy thriller — there’s always a mole) and it might be one of the very people who brought Will in (who include David Harewood, Tim McInnerny, and Jennifer Ehle). Harry and Will must work together to, a) find the mole, and b) stop whatever atrocity Qasim has planned next.

In case it isn’t clear, you don’t need to have seen the TV series to follow the plot, which is standalone in every aspect that seriously matters (there are certainly nods to the show, especially to its final season, and one fan-pleasing cameo. More would’ve been nicer.) However, a familiarity might help manage your expectations: The Greater Good feels like a wider-screen, (slightly-)bigger-budgeted version of the show, for good or ill. “Good” because, well, it should really, otherwise why call it Spooks? “Ill” because anyone expecting an action-packed thriller to rival Bond, Bourne, or Mission: Impossible will come away disappointed.

The trailers attempt to promise some of that kind of action, but they’re a bit of a cheat: what adrenaline the film has is mostly released in tiny bursts, scattered throughout. That strategy is fine if you’ve got the money to make each little burst a solid sequence, but when the entirety of some sequences is “jumping through a window” or “climbing a wall to get into a flat”, well… Sure, it looks good in the trailer — it promises lots of action in different places at different times — but that’s also a promise the movie can’t fulfil. The Greater Good certainly isn’t just a low-rent action movie — it’s driven by its plot — but if they’d saved up the filmmaking time, effort, and expense afforded to those single-dose action moments and poured it all into one sequence (in addition to the two or three fully-realised action sequences that the film does have), it might’ve paid dividends.

So what of that plot? As mentioned, the exciting contemporaneousness of Spooks’ storylines went increasingly AWOL as the series wore on, trading real-world issues for ludicrous government conspiracies or revived Cold War rivalries. Unsurprisingly, given the writers involved, the movie continues in that latter tradition. That’s a shame, because Spooks’ ability to engage with real-world issues in a thriller context was one of its best elements. It’s not as if we’re lacking in spy-related storyline-fodder in the real world — something Edward Snowden-y or about radicalised nationals would’ve been a good starting point. (Based on his accent, I guess Qasim is supposed to be an American who was converted, but that facet of his character isn’t explored.) At least they try to sub in some thematic relevance, raising questions related to doing what’s right versus doing what’s expected. Sadly that dichotomy isn’t explored as fully as it could have been either, but it’s definitely a constant and repeated factor.

You might not believe it from this picky review but, fundamentally, I did enjoy the Spooks movie. It largely retains the feel of the TV series (albeit without the moderately-memorable theme music — honestly, it’s like someone forgot to compose anything for the title credits. What were they thinking?!), and if they manage to produce a sequel then I’ll be sure to see it; but in this outing I can’t help spotting ways I thought it could’ve been even better. Consequently, as a film in its own right it comes across as a Bourne wannabe. On the bright side, it’s still better than The Bourne Legacy.

Spooks: The Greater Good MI-5 is available in the US through DirecTV from today, and in theaters and on demand from December 4th.