The build-up for this has been rumbling on for almost as long as that for the Olympics. Ever since Iron Man in 2008, the Marvel movies have been increasingly focused on working towards this ultimate ensemble get-together.

The films – IM 1&2, The Incredible Hulk, Thor and Captain America – were all broadly entertaining but more competent than inspiring and packed with teasers for this film. It was like sticking with a so-so TV series because of the promise of an explosive last episode.

So, given all that, when the film opens with the traditional opening gambit of a Transformers movie – a bunch of aliens plotting to enslave the earth by using a cube-shaped power source – it's a bit deflating.

But fear not; after some over-familiar scenes of scientists trying to deal with a porthole to another dimension, The Avengers comes good, very good indeed. It is perhaps everything fans hoped it would be.

It succeeds because the Marvel producers abandoned the general timidity of the series and made a real bold move. If I may use a football analogy, handing the film to Joss Whedon to write and direct is to imagine the FA giving Brian Clough the England job in 1982 and watching him waltz off with the World Cup (or at least the European Championship).

Whedon is a perfect fit. His dialogue feels like lines taken from speech bubbles and his version of The Avengers is epic, heartfelt and uproariously funny.

Granted, he has been handed a very talented squad to work with but he brings out the best in each and every one of them. He even manages to give the big screen its first great Hulk.

Mark Ruffalo is the third actor to have a go at playing his alter ego Banner and the first to see the role as something more than unrelenting misery. (I've said it before but Ruffalo at his best reminds me of a diligent Dean Martin.)

The green guy was previously undone by shonky CGIs and, though they are better this time, the improvement may be down more to the fact that he is not centre stage so any failings aren't so noticeable and that he is better suited to the lighter tone. Indeed the Hulk raises the film's biggest laugh.

If there is a weakness perhaps I'd say that Whedon's ability to deliver big action sequences isn't quite equal to his aptitude for droll quips, sight gags, plot reversals and unexpected emotional depth. Objectively, its citywrecking finale isn't quite the 3D spectacle Bay delivered in the last Transformers movie, but because you are so much more engaged by the characters and story, it's more entertaining.

It looks and sounds just like the film that ran in your head while reading superhero comics as a kid. Presuming Christopher Nolan can keep his end up, this will make a perfect counterbalance and companion piece to The Dark Knight Rises.

MARVEL AVENGERS ASSEMBLE (12A)

Director: Joss Whedon

Starring: Robert Downey Jr, Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson and Samuel L. Jackson

Length: 143 mins

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