After endless dull Sherlock Holmes incarnations, Guy Ritchie has perhaps achieved the impossible and turned the legendary detective (back) into a sexy, charming, action hero. Not only that, but the chemistry between his three leads could spawn a sequel.

This crime mystery sees Downey Jr abandon his 'Iron Man' mask long enough to dust off the stiff-upper lipped icon for modern day audiences to savour. Ironically, by staying faithful to Arthur Conan Doyle's late 19th century original stories, Ritchie has brought Holmes back to life. While remaining in the London-based period, he has flung open the previously welded-shut doors to reveal the man who became hidden under layers of tweed, a deerstalker and a cloud of pipe smoke.

Hired to find a missing girl, his new case brings him straight to the satanic rituals of Lord Blackwood (Ritchie regular Strong). Aided by his loyal companion, Watson (Law), Holmes thinks that he has solved the case but a number of curious events, including the reappearance of his former love interest Irene Adler (McAdams), make him think otherwise.

The role, for which Downey Jr revisits his 'Chaplin' British accent, has already earned the actor a Golden Globe nomination for Best Performance by an Actor in a Comedy or Musical. Judging by this performance, it will not be the only nod - or indeed accolade - that he receives.

Surprisingly, Law is perfectly cast as his brother in arms, Doctor John Watson, who also experiences a return to form. Gone is the frustrating portrayal of the Doctor as a bumbling fool and in his place is a formidable, capable ally - the witty exchanges and buddy bond between the two being one of the film's highlights. Another unusual yet perfect piece of casting is McAdams as Holmes' feisty femme fatale.

There is a distinctive Irish flavour to Hans Zimmer's ('Frost/Nixon', 'The Dark Knight') fiddle-based soundtrack in many of the action sequences, which are superb. Whether fight scenes, bomb blasts, sword/axe battles or vicious crimes, the slow-motion cinematography mixed with quality special effects are highly entertaining. Add to the mix a bare-chested, bare-knuckle fighting Holmes and you know this is a clever reincarnation of one of the original superheroes.

Despite some formulaic plot twists and Blackwood going unchallenged for way too long, the fast-paced plot never runs out of steam. Ritchie wraps up all his loose ends in a nice, natural conclusion.

Fans of the original novels and short stories may be disappointed to see that there is little more than a cursory hint of Holmes' drug history or indeed of the much speculated homosexual tie between the detective and doctor. Also the Holmes catchphrase, "Elementary, my dear Watson" - a popular misquote from the original material - is noticeably absent. Plus, we never did get to discover the identity of Sherlock's nemesis, Professor James Moriarty. Then again, there's always the sequel...

Taragh Loughrey-Grant