‘Once upon a time in Nazi-occupied France . . .” begins Quentin Tarantino’s long-mooted war opus, a blood-soaked fairytale divided into five hefty chapters. For most of the vengeful characters in Inglourious Basterds, there is no ‘happy ever after’ – the body count is staggeringly high and almost nobody reaches the end credits unscathed.

%movie(27312) However, Tarantino’s distinctive vision does end on an upbeat note as it plays fast and loose with historical fact – particularly with regard to the Third Reich – and splices genres to dizzying effect. The sharp mood swings, from the edge-of-seat nerves of the opening segment, to the grisly humour, which heralds the arrival of Brad Pitt’s gung-ho avenger (“Each and every man under my command owes me 100 Nazi scalps . . . and I want my scalps!”) take a little time to get used to.

And Tarantino certainly takes his time, rather indulgently allowing his pulpy fiction to unspool over the course of two and a half hours.

Thankfully, Inglourious Basterds is a return to form after Death Proof, his high-octane contribution to the Grindhouse double-bill, blessed with an Oscar-worthy supporting performance from Christoph Waltz as a sadistic German officer.

He ignites the opening chapter as Colonel Hans Landa, who interrogates a farmer suspected of harbouring Jewish families.

“May I switch to English for the remainder of this conversation?” asks Landa slyly as he bullies his suspect into submission, while the families he seeks lurk beneath the floorboards, holding their breath much like us.

Dozens of men, women and children perish in the subsequent bloodbath but one young woman, Shosanna (Melanie Laurent), escapes and reinvents herself as a cinema owner in Paris, where she plots her revenge.

Meanwhile, British Lieutenant Archie Hicox (Michael Fassbender) goes undercover to assassinate Hitler (Martin Wuttke) during a film premiere at Shosanna’s cinema, aided by leading lady Bridget von Hammersmark (Diane Kruger). Simultaneously, a gang of Jewish-American renegades, led by Lieutenant Aldo Raine (Pitt), plots to kill the upper echelons of the Third Reich with a single attack.

Operation Kino must succeed – the price of failure for the rest of Europe is unthinkable.

Inglourious Basterds is a stylish and blackly-humorous escapade let down by the disjointed structure and Tarantino’s reluctance to edit more judiciously.

The picture unfolds in fits and spurts, energised by Waltz’s scintillating portrayal of evil and by the directorial brio, particularly in the explosive finale.

Pitt is forgettable in a quirky supporting role, while Mike Myers enjoys a cameo as a doddering British general and Samuel L Jackson adds an unnecessary voiceover.

The violence is graphic but used sparingly, including a cinema shootout that conjures memories of Brian De Palma’s Scarface.

If the writer-director had just scalped his own vision by at least 30 minutes, this might have been his masterpiece.