Twenty years after the events of the first film, Renton (Ewan McGregor) returns to Edinburgh and retraces his old friends, Sick Boy (Jonny Lee Miller) and Spud (Ewen Bremner), whilst trying to make sense of the intervening time. Meanwhile, Begbie (Robert Carlyle) schemes his way out of prison and begins to wreak havoc.

Legacy sequels are a tricky thing. In almost all successful examples - such as Creed or Star Wars: The Force Awakens - there is a sense that the story is continuing through fresh blood and new eyes, but with familiar faces to guide us towards them. 1997's Trainspotting might have ended on a vaguely hopeful tone, but it's made clear from the get-go that there is nothing hopeful for what lies ahead. We're introduced to Spud through a blackly funny montage of his ineptitude with time, Sick Boy through lines of cocaine and a blackmail operation he's running and, finally, Renton who stumbles through Edinburgh in a bewildered state. From the opening, it's clear that the world has changed completely - but the gang have been in a holding pattern for twenty years.

That in itself poses the question - how do you make this work and be fresh? The answer is that you can't, and that's what makes T2: Trainspotting 2 kind of brilliant. There's a scene where Sick Boy and Renton have done a few lines of cocaine and are blabbering on about George Best's exploits on and off the pitch to a bewildered Bulgarian prostitute, played by upcoming actressAnjela Nedyalkova. She then, in Bulgarian, explains to them both that they're obsessed with the past and that where she comes from, the past is something to be escaped and that nothing good comes from it. It's been done, it's had its day and that's the central crux of the film - looking back over the past gets you nothing. How many legacy sequels would have the courage to stick two fingers up to the audience like that?

As you'd expect, the performances across the cast are riven with intricacies that can only come from twenty years of experience. McGregor's portrayal of Renton is now of a weakened, oft-bewildered man who's been handed a new lease of life and chooses to eke out a bland and meaningless existence. Bremner's Spud is caught in a cycle of addiction, failure and acknowledgement of both whilst Miller's Sick Boy is clutching for meaning in a meaningless existence. The film, however, belongs to Robert Carlyle's career-best performance as Begbie. In the first film, he was a force of nature and terrifying to behold. Here, he's a beaten man who struggles to connect with his long-suffering wife and son, whom he tries unsuccessfully to mould in his own image. There's a deep, deep well of sadness behind Carlyle's portrayal that makes for some uncomfortable moments and some cracking comedy as well. It's the kind of performance that you can only get with an actor who's lived the life and had more than his own share of regrets.

John Hodges' screenplay perfectly balances the pathos of living in a circle and the comedy that comes from trying to move out of it. There's so many points in the film where you think it's going to hop back into the old ways; signified brilliantly in one scene where Renton almost plays the now-infamous Lust For Life song and stops himself immediately. Yet, it never does and you never get that pop you're hoping for. Instead, the story makes you look your need for nostalgia and reverence for the past right in the eye and acknowledge it, the same way all the characters in the film have to acknowledge it. It's heavy stuff, but again - how many legacy sequels would attempt to honestly examine why it's there in the first place? Boyle's use of fast cuts and music is assured and as confident as you'd expect, and the use of footage from the first film is masterful in places. Again, it acknowledges the fact that the past is never what you want it to be, and that that your hopes then don't always materialise - but we have to find contentment where we can.

In all, T2: Trainspotting is equal parts hilarious and poignant and exactly the kind of sequel the original film needed.