As Jason Bourne flits around London and New York making trouble for what’s left of Treadstone, a group of shady men go about safeguarding their own secretive activities. When Bourne exposes Treadstone, a series of convoluted join-the-dots links means it could bring them down too, so they set about destroying their risky initiatives, including killing a bunch of medically-enhanced operatives. What they didn’t count on was one surviving…

That basic setup covers roughly the first 30-40 minutes of The Bourne Legacy. Normally I’d hate to describe so much of a film, but it’s not my fault that co-writer, director and Bourne series veteran Tony Gilroy takes that long to get his story up and running. And it’s another 20 minutes before the real meat-and-potatoes of the tale begins.

And it feels it, too. About 52 minutes in I paused it and went to the kitchen. Not for any particular reason; I just needed a break. There, I saw a slug crawling into my dog’s water bowl, drinking the water or something, I don’t know. I’d never seen that before. I ended up watching that slug slowly edge around the bowl for 15 minutes or more rather than go back to the film. It’s that engrossing.

Gilroy has written or co-written every Bourne film to date, so you’d think he knows his way around the franchise — and he does, but perhaps too well. Each Bourne sequel has basically relied on the same formula: “the conspiracy was bigger than you thought, and now the next level up want Bourne dead”. That was fine in Supremacy — indeed, it took characters left dangling from Identity and wrapped up their roles. For my money, Ultimatum felt like it re-hashed this storyline, bringing in new characters to force a new level of backstory and hierarchy. (Clearly most viewers didn’t mind, as it’s widely regarded as the best Bourne film.)

And Legacy recycles this idea for a third time. Now, Treadstone and Blackbriar are just two of many such programmes run by the CIA and/or some shadowy higher organisation I’m not sure is real. On the bright side, they’re not after Bourne, but new escapee Aaron Cross. Not that it makes a huge amount of difference.

If such a repetitious story wasn’t bad enough, Gilroy spends a ludicrous amount of time setting it up. The beginning of Legacy overlaps with the end of Ultimatum, showing us in dully intricate detail what the numerous new CIA characters were doing during that time. And intercut with that we have our new hero wandering by himself across Alaska. For half an hour. This isn’t an art film meditation on isolation, it’s an action thriller — get a bloody move on!

What did Gilroy lose between Ultimatum and this? Well, co-creators. He co-wrote Identity and Ultimatum, and had two different directors across the first three films. Here he’s responsible for the story, co-writing (with his younger brother), and directing. He undoubtedly has some degree of talent, but maybe the other voices were essential to honing it. The other thing a fresh perspective could bring is fresh ideas. If Gilroy has rehashed the same basic plot three times now, surely they need someone with a new story to offer?

Perhaps also, after four films, he’s too close. Clearly that has advantages for remembering the intricacies of the timeline and continuity, especially with the trilogy’s increasingly complex web of conspiracies and conspirators; but maybe Gilroy has become too deeply embroiled in that. After all, he thinks it’s OK to spend the first half hour of the film connecting up the dots between the previous story and his new plot — who really wants that? That’s for geeky fans to do later.

And yet, for all that, the timeline doesn’t quite make sense. If we assume Identity is set in 2002, because that’s when it was released, then Supremacy is two years later, in 2004. Ultimatum is six weeks after that, so late 2004 or early 2005, and Legacy is immediately after that (as I said, the start overlaps). So, it’s set seven years ago? But a character finds a moderately key plot point on YouTube as if it’s the most natural thing in the world… but the very first YouTube video wasn’t uploaded until April 2005. I guess the films operate on a sliding timeline now, much like long-running superhero comics or the Bond films. That or The Bourne Identity is really a sci-fi film set in the Future Year of 2009. Considering the ‘science’ brought to bear in Legacy, perhaps that is the idea.

This is also the first Bourne film that leaves its storyline truly open. The other sequels had threads to pick up on, obviously, but if the series had stopped after either Identity or Supremacy, you’d have still had a complete tale (or Ultimatum, of course). It’s ironic, because this is also the first time I’ve been left with no desire to see a follow-up. The ending reminded me a bit of Saw IV, actually. For those who don’t know their Saw films, that takes place concurrently to Saw III, following different characters and a different storyline. At the end, the two films come together, adding a few seconds more story to what we saw at the end of IV, and ready to move on with unified purpose (well, sort of) in Saw V. Legacy feels like it concludes the same way: we’ve been introduced to new bad guys and a new hero, and the events that ended Ultimatum have been given a few seconds more development with a new twist; so now all is ready to rejoin where we left Bourne himself and continue afresh. Except Matt Damon seems to have ruled out that idea already. And, like I said, do we really want more of these characters and their increasingly ludicrous levels of conspiracy?

Legacy isn’t all bad. When it finally moves up to second gear (after a whole hour) there’s the occasional good action sequence. The requisite Bourne car chase is replaced by a bike chase, but I’d happily argue it’s at least the equal of any of the series’ other road chases — the only part of the film that can stand up to its predecessors, because the other fights and foot chases don’t have the same edge. Indeed, a rooftop/alleyway chase in Manila is just a rehash of Ultimatum’s Tangier sequence, but not as exciting. And through all that, the story remains resolutely uninvolving.

And don’t get me started on the cast. Jeremy Renner is fine as an action man but doesn’t deliver any other significant likeable qualities here (and I don’t think that’s his fault). Rachel Weisz is normally brilliant, but here is reduced to a snivelling plot piece. They’ve made her character a Clever Scientist, which is presumably supposed to make her a Strong Female Character too, but that’s not how it’s played at all. Edward Norton is wasted staring at monitors; Albert Finney is literally wasted, his one meaningful moment relegated to the Blu-ray’s deleted scenes section; Zeljko Ivanek gets a pivotal character but is underdeveloped and so his talents are wasted; and some actors from previous Bourne movies appear to be credited merely for use of their photos, until they turn up for ten-second cameos near the end that you’d rather weren’t there because it means someone is planning on a Bourne 5.

After the muted reception Legacy got on release I was expecting it to be mediocre — or perhaps, if I was lucky, underrated — but I thought it was mostly just boring, worse than I’d heard, and not even close to any of the previous Bourne films. They’re exceptional examples of the action-thriller, of course, but this isn’t even good as a routine genre entry, because it’s quite spectacularly dull. I do believe they could have continued this series without the character of Jason Bourne — there’s potential in some of the ideas here. But this version just doesn’t work, as a compelling film or worthy successor.

The Bourne Legacy is on Sky Movies Premiere at 4pm and 8pm every day for the next week.

It featured on my list of The Five Worst Films I Saw in 2013, which can be read in full here.