film Heath Ledger and Lily Cole in The Imaginarium of Doctor Parnassus

Directed by Terry Gilliam. Starring Heath Ledger, Christopher Plummer, Verne Troyer, Andrew Garfield, Lily Cole, Tom Waits, Johnny Depp, Jude Law, Colin Farrell. 12A Cert, gen release, 122min.

This curious fantasy is an underwhelming send-off for Heath Ledger, writes DONALD CLARKE

SO, AGAINST all the odds, here it is. It hardly needs to be said that The Imaginarium of Doctor Parnassusis the film that poor Heath Ledger was working on at the time of his death. After a few weeks of fretting, director Terry Gilliam, having survived the odd calamity on the sets of Brazil and The Adventures of Baron Munchausen, set out to complete the film using three celebrity stand-ins.

What's it like? Well, this bit's okay and that bit's quite interesting, but there's no getting away from the fact that Doctor Parnassuslooks like a project whose star died half-way through filming. It's a fascinating curiosity. It's an impressive logistical achievement. But it's not a very good movie.

That said, fans of Terry Gilliam need not despair. There is evidence here that, had grim fate not intervened, Doctor Parnassusmight have marked a real return to form.

Events begin with the titular hero, an ancient magus played by

a magnificently dignified Christopher Plummer, being transported through contemporary London – all gothic shadows and yawning alleyways – in a wagon that folds out to form a rude theatre. The Doctor’s company comprises his lollipop-headed daughter (Lily Cole) a world-weary little person (Verne Troyer, of course) and an eager young actor with eyes for the leading lady (Andrew Garfield).

It transpires that, many centuries early, the Devil (in the eccentric form of Tom Waits) made a characteristically crafty pact with the impresario. The mortal has become immortal, but, as the film begins, he is confronted with the heavy price he must pay in return.

Gilliam makes ingenious use of various Thameside locations to summon up an alternative, largely nocturnal London that could have sprung from a collaboration between Charles Dickens, Alan Moore and The League of Gentlemen. Plummer, whose carefully modulated fragility contrasts nicely with Waits’s less subtle showmanship, is on top form, and Garfield makes something lovable of the wide-eyed ingenue.

Sadly, the film begins to go off the rails the minute the troupe encounter Ledger’s Tony Shepherd, a rogue and a charmer, suspended beneath the arches of Blackfriars Bridge. As the stranger becomes inducted into the group, the drama starts to deal in the wrong kind of weirdness.

It looks as if Gilliam has not only shot fresh scenes, but has allowed already extant sequences that might otherwise have been trashed into the final cut. Much of the dialogue between Ledger and Garfield has the awkward, forced feel of improvised theatrical workshops and, as a result, fits uncomfortably with Plummer’s more balanced speeches.

Then, when Ledger shuffles off screen and his replacements – Johnny Depp, Jude Law and Colin Farrell – swing in, the film totally loses its bearings and descends into narrative mayhem.

The conceit that allows this peculiar innovation is acceptable: Ledger repeatedly passes through Parnassus’s magic looking glass and changes appearance. And all three actors make a good fist of embodying different strands of the anti-hero’s personality.

One scene, during which Depp mourns icons such as James Dean and Princess Diana who died too young, is all the more poignant for its having been in the original script. However, the melange of random imagery and jerry-built surrealism is never attractive enough or funny enough to make up for the loss of focus.

This is one of the few Gilliam failures where, in the closing sequences, you are unlikely to say: "Well, at least it looked nice." Indeed, as the film flails towards its messy denouement and ever-more tediously whacky events unfold, The Imaginarium of Doctor Parnassusbegins to look more and more like another famously patched-together botch-job from an earlier era.

I'm sure Terry Gilliam didn't mean to reanimate the spirit of Casino Royale(the 1967 one, I mean), but that is, sadly, what he has achieved.