Every time I see a new musical made from a recent-ish film, I wonder if this could be ‘the one’, the one that jumps the shark and enters the canon of the regularly performed. With composers James Lapine (Into the Woods) and William Finn (Spelling Bee, Falsettos) you’d think Little Miss Sunshine stood a better than average chance.

It’s a 2006 ‘road picture’ which has had to be converted to the confines of a chamber-sized venue so much of the ‘action’ is the characters configuring and reconfiguring their VW camper van by stacking chairs on a trolley in the middle of the stage. There’s a nifty revolve, and some enthusiastic humping by the cast, and to an extent it works.

What doesn’t work, at all, is the marriage of an entirely forgettable musical theatre score to the tale of a dysfunctional family travelling from Albuquerque to California to seize a last-minute opportunity for their little moppet to take part in a beauty pageant.

Mehmet Ergen’s production seems unclear whether it’s a working out of their family drama tinged with suicide, a broken marriage, a completely withdrawn teenager and the death of a coke-snorting sex-mad grandfather – or a ‘madcap caper’, and so succeeds at neither.

It’s equally unclear whether the family is meant to be most like the Joads (Grapes of Wrath), the Clampetts (Beverly Hillbillies) or The Griswolds (National Lampoon) and the actors riochet between them.

The score is played by a disappointing five-piece string-heavy band which feels entirely wrong for a bouncy musical. All the lifeless songs land flat and the audience seems bemused.  This morning I simply could not recall a single tune.

Little Miss Sunshine is a great vehicle for a child to shine as Olive, the bespectacled small girl who is accidentally entered in the beauty pageant final – and while last night’s actor was cute and funny and maintained her American accent, in the ‘big number’ where she has to strip (I know, it’s appalling really), sing and dance, the lyrics were inaudible.

It’s quite an uneven production, and the excellent talents on stage feel wasted. Laura Pitt-Pulford as the wearied mother is downbeat and naturalistic, Gabriel Vick as her failing-at-life husband has tremendous energy but nowhere to take it, and as ‘Uncle Frank’ Paul Keating enjoys his second suicidal experience at the Arcola following the excellent Kenny Morgan.

Handed two cameo roles, Imelda Warren-Green has a lot of fun as both a pert hospital administrator and a posturing Latina beauty queen, but they are both acted up to Catherine Tate sketch-show levels. There’s so little to engage with or care about the central characters it’s easy for Gary Wilmot as the porn-addicted grandpa to upstage the lot of them.

But he dies in the interval.

So did the show.

until May 11, then touring till late July