The BFG review: It's no catastrophe, but it's no E.T.

Steven Spielberg directs Roald Dahl's The BFG for Walt Disney? Just back up the trucks and shovel in the money, why don't you?

Let's not be too cynical. This undeniably warm-hearted film - playing out of competition at Cannes - promises unstoppable monsoons of charm.

The sweet-voiced, eccentrically featured Mark Rylance is ideally cast as the titular Big Friendly Giant and the recent Oscar winner does not disappoint.

Motion-captured into an only faintly grotesque version of himself, he delivers the lines in a Kentish burr that – halting to emphasise each inventive malapropism – is ideally suited to a film for young children.

We expect Spielberg to unearth juvenile talent and, sure enough, Ruby Barnhill is charming as young Sophie. She has sharp comic timing and the ability to convey vulnerability cloaked in no-nonsense courage.

And yet. The film does not sparkle as it should. The art design is a little too safe. The build up to a final absurd conflagration is too leisurely. The pathos has gone missing. The CGI looks like nothing but CGI. Calm down. It's not a catastrophe in the style of Spielberg's Tintin. But nobody is going to confuse it with ET.

Mind you, suggestions of that early film – released the same year The BFG was published – are present in the opening minutes. Sophie is prowling about the halls of her orphanage when she becomes aware of a presence lurking in the street outside. A dark shape emanates from an alleyway. Even if Spielberg were not behind the megaphone, one might think of Elliot discovering his new friend in the back garden. The BFG (for it is he) scoops Sophie up and brings her to a gloomy kingdom somewhere beyond the clouds. He has no malign purpose, but, now Sophie has spotted him secretly collecting dreams in the everyday world, he cannot trust her to keep silent. After her nerves have calmed, she becomes fond of her protector and his eccentric home: motorway signs for trays, whole ships for occasional seating.

Anybody who was born after 1982 or has had children since that date will already know the story. The late Melissa Mathison's script does not deviate too dramatically from its source. We get the most unusual sight of Queen Elizabeth (a storming Penelope Wilton) dining with the BFG and having bottom issues when she consumes his green fizzy pop. The oddest moment arrives when, alerted to looming disaster, she phones "Ronnie" (Reagan) and "Boris" (Yeltsin, I'm guessing) to ask for help. Is this the 1980s or the 1990s?

It is, of course, that generic, polished version of England that occupies all times and no times. Virtually the first thing we see is a Mini driving down a cobbled street past a welcoming public house. There are no "peelers", but the Queen does unleash Grenadier guards on intruders.

It may seem facile to suggest that this stuff will work only for smaller children. After all, that is the target audience. Spielberg was, however, instrumental in launching the school of family film that genuinely plays to all ages. The BFG feels, in short, awfully old fashioned. It will make hundreds of millions.