As Harry Potter fans know, the fourth of J. K. Rowling's saga is a lengthy tome but, even at 157 minutes, a lot is left out. As a result, it sometimes feels like edited highlights.

We get straight into the plot without even a glimpse of Harry's miserable muggle summer: the Lord You Know Who is still haunting Harry's dreams. This year Hogwarts is hosting the Triwizard Cup, for which Harry is surprisingly enlisted. At 14, he's under-aged, competing against much stronger wizards (Pattinson, Ianevski and Poesy). But more terrifying than battling dragons or underwater creatures is the need to ask a girl to the Christmas dance. And those sinister dreams won't stop.

This feels like a much bigger film than previous instalments. The story has an epic horror scope; we know from the beginning that something seriously awful is afoot, and Newell deftly avoids the mistake of making a kids' movie in which even the worst threat feels safe. He also focuses on characters, not effects, so that as it reaches the frighteningly nasty climax, there's a huge rush of unexpected emotion. And as Harry and pals Hermoine and Ron (Watson and Grint) continue to grow up, they're facing real adolescent and adult issues.

Ratcliffe handles the dramatic scenes beautifully, shows reluctant-but-dashing flair in the thrilling action sequences, and even gets a couple of beefcake moments. Watson and Grint are also allowed to develop their characters even further than JK Rowling does in her books. Of the returning teachers, Gambon gets the most screen time, while Smith and Rickman get the scene-stealing moments. The new cast's stand-outs include Richardson's pesky journalist and Fiennes as Voldemort incarnate (although his look is a little extreme).

The film's star, though, is the wonderful Gleeson as Mad-eye Moody, investing each scene with a devilishly gleeful twitch. His roving eye is a hoot. Gleeson has a whale of a time as a kind of Irish Long John Silver, always hinting at danger lurking beneath his apparently kindly surface.

These films get better and better technically. The effects are nearly seamless, and the story rockets along like Harry on his Firebolt. Newell balances the comedy and thrills expertly, and dares to notch it up, reflecting the fact that these kids are maturing. Which bodes well for the even darker times ahead.

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