Gangsta Granny review: David Walliams’ children's book shines as a theatrical show ★★★★

His debt to Roald Dahl is acknowledged by him and his tales of ordinary children doing extraordinary things are acclaimed and (justly) loved almost as much as the great Roald's.

His books are also ripe for stage adaptations and this version (which has already toured the country for 18 months and is having a month in the capital) is a colourful and cheery take on his book about a boy’s relationship with his Gran.

Our hero Ben (Ashley Cousins) cannot abide Friday nights when he is forced to see the old lady while his parents razzle their dazzle at their beloved ballroom dancing classes. Granny is boring and cooks things with cabbages.

She also farts a lot – a habit which director/adaptor Neal Foster makes the most of by including a bottom explosion almost every five minutes. I would normally condemn this as childish but I have young children of my own and Foster clearly knows his audience.

Of course Ben's Granny (a lovely performance from Gilly Tompkins) is not all she seems and he unearths a tale about her being an amateur criminal, leading to a dramatic heist to steal the Crown Jewels. It’s a great little story and everything (as many children and those parents like me who have read this story countless times at bedtime or seen the 2013 BBC adaptation will attest) is not as it seems.

As Ben, Ashley Cousins is charm itself, while Gilly Tompkins' Granny is both a frail old lady who stiffens when sitting down and a vibrant woman of many secrets and with so much to offer. And that is what this story is all about. It’s a message that is hammered home a little forcefully, but you cannot help leaving this theatre with the understanding that old people are not to be dismissed. And quite right, too.

As a show it's got the exuberance and comic brio of the books – but with a bit of visual dazzle too. The set unfolds almost like a picture book, moving from bedroom to ballroom, to front room, to Granny’s modest terraced house and eventually to the Tower of London with striking concision and imagination. At the Tower they come across a rather interesting visitor who puts in a fun little cameo, but I won't say any more. I don't want Gangsta Granny to come after me for leaking secrets.