By Caroline Westbrook BBC News Online

It is no surprise that the new Mel Gibson film arrives in the UK on a wave of hype.

Not only has it become one of the biggest films of the summer, raking in over $200 million in the US, but it boasts the kind of subject matter audiences love.

The mystery of crop circles and a director (The Sixth Sense's M Night Shyamalan) who you just know can do justice to this kind of thing is an exciting combination.

But away from the credentials, is it worth the wait?

Joaquin Phoenix puts in a brilliant performance

In some ways, definitely - Signs boasts more than its fair share of tense and scary moments, tapping into peoples' paranoia and fears to winning effect.

However, its tendency to rely on OTT histrionics and frankly daft-looking monsters prevents it from being the classic chiller it had the potential to become.

Gibson takes over where Bruce Willis left off in The Sixth Sense and Shyamalan's more recent film Unbreakable as the ordinary man plagued by seriously weird goings-on.

He is an ex-clergyman trying to bring up his two small children after the death of his wife.

Distressed pets

It is obvious from the start that all is not as it should be, with overly distressed household pets, shadowy figures appearing at night, and of course the small matter of huge crop circles appearing in the fields around their remote Pennsylvania home.

When mysterious lights begin appearing in the skies over every major city in the world, things begin to get really strange.

Shyamalan, a master of the slow build-up, favours a creepy sense of menace over sudden unpleasant shocks, although the film does have a healthy amount of those as well.

The children try to fend off the aliens

The film's strength lies in the way he taps into the fear of the unknown, and how people can become addicted to the inevitable media onslaught in times of crisis.

Chilling

One sequence, in which Gibson's brother (a terrific Joaquin Phoenix) has spent all night watching TV coverage of the emerging lights in the sky, is chillingly reminiscent of the days following 11 September.

Memories of people spending every waking hour glued to the screen for fresh information or for a shred of non-existent good news are still close to home.

But there are lighter moments too, from Gibson's children donning tin foil hats in an effort "to stop the aliens reading our minds" to the woman who insists on confessing all her sins to him because she is convinced the end of the world is nigh.

It is a shame that for all its plus points, the film lets itself down in other areas - offering ridiculous looking ETs that would not be out of place in a 50s B picture and muster up more unintentional titters than thrills.

While you can usually rely on Shyamalan to pull something unexpected out of the bag at the end, this time around the denouement is frankly risible.

Ultimately, Signs never quite replicates the brilliant simplicity of The Sixth Sense, but makes for far more enjoyable viewing than the snail's-paced shenanigans of Unbreakable.

It is flawed, certainly, but is nevertheless an interesting, thought-provoking picture from one of the most exciting new directors around.

Signs is on general release in the UK.