It must have been a very daunting task to transfer Stephen Sondheim's Tony Award winning smash of 1979 into the lean, mean cinematic vehicle currently on release. Sondheim's musicals have had a rough ride in the past with rather uninspiring versions of 'A Little Night Music' and 'A Funny Thing Happened On The Way To The Forum' suggesting that the composer's often notoriously complex works did not transfer particularly well to the screen.

Evidently, he hasn't been precious about this adaptation by director Tim Burton and writer/producer John Logan. He's allowed the makers to cut the running time down from its original three hours, to chop out whole songs, verses of other songs and remove the Greek chorus that bookended the various acts of the original stage version. That the film does not actually suffer from this stripping down of the material is testament to his own belief that the film should not be a carbon copy of the stage version and of his trust in Burton and Logan to be faithful to the material.

Sondheim's later works - 'A Little Night Music', 'Follies' 'Company' and then 'Sweeney' - make the move away from the traditional structure of musicals where the action of the plot tends to stand still whilst the songs are sung and they embrace the use of songs as narrative in itself. 'Sweeney' is one of the finest examples of this, where the entire narrative is sung. Fortunately, this is also the approach the film takes too and it probably felt like an enormous risk to just simply open the film with the characters singing and then to just keep going! How younger audiences would react to this was probably the greatest concern for the production team.

They needn't have worried. Firstly, the orchestrations by Jonathan Tunick of the original Sondheim score both respect and beautifully augment the original and give the film a wonderful soundscape using motifs and recaps to drive the narrative and songs and, secondly, both Johnny Depp and Helena Bonham-Carter manage the songs in a very unexpected but competent way. There are moments in Depp's delivery where he clearly doesn't have the range but these are fleeting moments in a truly mesmerising performance where he thoroughly explores and portrays Todd's pathology. And both he and Bonham-Carter have realised that for the cinematic treatment of this operatic material to succeed there is a great need to pull it all right back and make it very intimate rather than simply bellowing it out in theatrical mode. The film wouldn't work that way. Bonham-Carter sort of sing-whispers her way through the libretto and it really works. It's almost like she's gossiping to the audience about the gory goings on. She also gets a big slice, if you pardon the pun, of the gallows humour in the film. It's hilarious when, after Sweeney's dark reverie throughout 'Epiphany', which takes him on a bitter journey into the recesses of his psyche, she snaps him into reality with '...that's all very well, but what are we gonna do about 'im ?' referring to the corpse of Pirelli languishing in its trunk.

I did squirm initially at Depp's cod Cockey, Bowiesque singing but that feeling completely dissipates as you're drawn into the film. He's pretty good at merging the sung dialogue together with his take on the character as an actor. Other performances of note are certainly Timothy Spall's very camp Beadle Bamford, a grotesque played with supreme relish, and the equally arch and thrillingly perverse Alan Rickman as Judge Turpin. Both performances are very fruity, ripe and perfectly in keeping with the Grand Guignol setting. And the tense, edge of your seat duet 'Pretty Women' between Depp and Rickman is one of many fine highlights in the film. Sacha Baron Cohen, as Pirelli, Todd's tonsorial rival, adds another tongue in cheek, low comedy moment too and he shows a fine aptitude for this work which in itself is a revelation. The duet, 'Not While I'm Around' between Bonham-Carter and Ed Sanders as Toby, is gloriously moving and beautifully performed but again is undercut by the morbid humour of Mrs. Lovett then flinging Toby into the bake house with its dismembered corpses and raging ovens despite the previous emotional overtures between the two characters.

It is a gory film but it has a heightened, almost slapstick, quality to the blood letting. It becomes ever more ridiculous but that's exactly as it should be. You know you shouldn't relish it but you can't help yourself. It's grim and gruesome and funny all at the same time. But that doesn't diminish the theme of the dehumanising effect of violence at all. And its dark take on the mass consumer society that constantly eats itself is still intact and perhaps even more relevant than it was in 1979. In the end, the main question is 'do you sympathise with Todd?' and his acts of vengeance. I would say that to an extent you do and you must in order to make any sense of the shocking events, after all his wife and child are taken from him and he's wrongly imprisoned for 15 years, but the moral coda is that in whatever you do to take your vengeance be careful not to destroy your soul. And to pollute the minds of those around you. In this dog eat dog world, the ultimate, thrilling expression of it is when Todd throws Mrs. Lovett into the bake house oven. It makes you gasp.

Visually, it looks sumptuous. Not pretty but gritty, grey and with enough atmosphere to feel the dirt and blood beneath your fingernails. Cinemaphotographer Dariusz Wolski bleaches most of the colour out of the frame but then startlingly highlights and picks out various costumes - Pirelli's electric blue outfit, Turpin's golden britches - and the fountains of blood amidst the smudgy chiaroscuro of his endeavours. The sequence for 'By The Sea' sees the screen burst into vivid colour momentarily as we explore Mrs. Lovett's impossible dreams. Burton's direction isn't overtly flashy here but there are some great swooping camera movements and amazing tracking shots that embellish his unflinching gaze at the throat slitting violence and certainly remove any feeling you are watching the original stage performance. He seizes the Grand Guignol of the story and places it very firmly in the centre of the screen.

It's a satisfyingly thrilling experience, full of grisly gallows humour, the bleakness of English Gothic melodramas, stunning music and lyrics from Sondheim, and once you accept the sung narrative and the broader performances, a rollickingly good, bloodthirsty story.

Sweeney Todd: The Demon Barber Of Fleet Street (Cert 18 - Released 25th January 2008 - Directed by Tim Burton)