THE third instalment of the Harry Potter phenomenon has hit the big screen and this time its darker than ever.

Following the lead of author JK Rowling, new director Alfonso Cuaron moves away from the cheery mood of the previous two film versions to produce an altogether more grim and scarier atmosphere in The Prisoner of Azkaban.

The film follows Harry's third year at Hogwarts with new problems and a fresh fear to deal with - the release of the murderous villain Sirius Black.

With the ghost-like demeantors ready to deliver their kiss of death swarming around the castle grounds and the shape-shifting boggarts thrown in for good measure, there are some pretty scary moments in this film, especially for youngsters.

But the real star is the special effects and scenery which, at times, are truly breathtaking. Hogsmeade is exactly how it is imagined.

As in the other two, it is the movie's adult stars that stand out in the cast. David Thewlis is fantastically mixed-up as the dapper Professor Lupin while Emma Thompson's visions of "grim" for Harry as madcap fortune-telling Professor Trelawny steal the show. And no more praise is needed for Alan Rickman's portrayal of Snape.

Now to the bad part. Daniel Ratcliffe.

Ok, so he looks like Harry, but there is a sub-editor here in the Guardian offices who looks like him but I'm not advocating he joins the cast.

I'm sure Ratcliffe is a nice enough lad, but he can't act. Dippy, posh kid maybe, suspense or emotion, no way.

And it's a real shame because try and avoid it though you might there are moments in this film spoiled by his failings.

Now we had the luxury of watching the film complete with subtitles, which described not just the language but noises. Hence the surprise when, after one of Ratcliffe's lower moments in the film, the word "pants" appeared. Now some may say that it was in reference to the noise of the passing Sirius' animagnus, but I'm not so sure ...

6/10 Moody magic but time to release Ratcliffe from his spell