Nearly all dud films fall into one of two categories.

Sometimes, you sit watching in open-mouthed disbelief that such a pile of rotting effluence ever got a green light – I still break into a cold sweat when I think of the talented Brendan Cowell’s clichéd cricket comedy, Save Your Legs.

And sometimes it’s easy to see what the film was envisaged as being but, somewhere along the way, it just failed to come together.

Robert Zemeckis’s Allied falls into the latter camp.

The story of spies, love and double agents with the backdrop of Casablanca and London in World War Two surely had the hallmarks of a winner. Add the directing pedigree of Mr Zemeckis and a strong, mainly British cast headed by international stars Brad Pitt and Marion Cotillard and you’d probably bank on this one being a commercial and critical blockbuster.

Sadly, it just doesn’t work.

Screenwriter Steven Knight has enjoyed success and Oscar and BAFTA nominations for Dirty Pretty Things. But other work of his has been found wanting – The Hundred Foot Journey, Closed Circuit – were both decidedly mediocre. He has filled Allied with implausible plot devices, unconvincing characters and some pretty average dialogue.

The film starts with Brad Pitt, an intelligence officer with the Royal Canadian Air Force, teaming with French Resistance heroine, Marion Cotillard, in Casablanca to assassinate the German Ambassador. Their goal is achieved with too much ease, their escape far too easy as row upon row of German soldiers run into their path to be mowed down like hapless aliens in a computer game. How you longed for an ingenious escape route such as Ryan Gosling’s at the start of Drive.

Swiftly falling in love, the couple head to London for marriage, a child and domestic bliss. But this ideal is turned upside down when British Intelligence inform Pitt his wife is suspected as being a German agent. He must feed her false information and then kill her should it become clear she’s passed the bait to the Goons; should he fail to do so, he will be hanged for treason. It’s preposterous stuff, and following events and the film’s denouement are equally ludicrous.

Robert Zemeckis must take the blame for the film’s poor pacing. Events in the first third of the film in Casablanca whizz by too quickly, but when events move to England, it drags. Zemeckis also has no feel for a war-torn and blitzed London, seemingly unaware of rationing, shortages and severe austerity. The scene of Cockneys round a pub piano singing The White Cliffs of Dover was trying too hard.

Cinematography, production values and costumes were good; the actors did their best with the given script.  But it wasn’t enough to save a film which promised so much.

**