"I'm up for it - it's a bone-hard medical fact," John Wilmot, 2nd Earl of Rochester, informs the laydeez in the audience in the opening scene.

And, indeed, he is up for it. He's up for dumping his teen bride Elizabeth (Pike) and their damp pile in the Oxfordshire countryside and whoring his way around London.

He's up for ridiculing his fellow, feckless aristos - including a periwigged Johnny Vegas - with impudent verse and sarcastic stanzas in the sordid taverns of the town.

Rochester's even up for winding up the court of King Charles II (Malkovich with dodgy false nose) with a performance including, erm, sex aid-wielding wenches and a vast willy on wheels.

However, his teflon coating of acid-tongued arrogance married to claret-fuelled self-destruction is pierced when he meets aspiring actress Elizabeth Barrett (Morton).

Her rigid self-assurance and alien incorruptibility in a world of grimy strumpets and pliable hangers-on hits Rochester hard and provides an irrisistible lure to the wag-about-town.

Commercials director Laurence Dunmore's debut feature is a real slow-burning pleasure helped - in no small measure - by a marvellous script from playwright Stephen Jeffreys.

Packed with potty-mouthed bon mots, it's relished with a swagger and a sneer by Depp in a philandering performance that's pretty much faultless.

Reflecting the Restoration's enlightenment in the sciences and arts, it also finds time to have a pop at the French - apparently fornication with strangers in the streets of Paris is compulsory.

It looks like it was shot through a tureen of Windsor soup but this London has the desperate air of authenticity - all swampy streets and candlelit murk.

Morton is terrific as the actress who would sell her body but never her ideals and there's solid support from Malkovich and Richard Coyle as his long-suffering manservant Alcock.

However, it's Depp as the firebrand who burns out all too soon that makes this one of the unsung pleasures of the year.

Tim Evans