What We Did On Our Holiday

The joke is that grown ups tell lies and children know they do. The age of innocence belongs to another century. What remains true is that families fight and marriages end in tears.

The title sounds like a primary school exercise which is where the irony comes in. This lot are not on holiday, not really. Doug (David Tennant) is going through a divorce. Abi (Rosamund Pike) lives in another house with their three kids who are perfectly aware that when Mum and Dad get together there's going to be shouting. So far so predictable!

Of course, Tennant and Root have enough charm to overcome Doug and Abi's antagonism, making it subservient to the plot which is about driving to Scotland for Grandpa's (Billy Connolly) 70-something birthday and pretending nothing's the matter.

He's the classic angry old man, great with the grandchildren ("If your intentions are good it's OK to lie"), encouraging them to be themselves and break the rules. He has terminal cancer which adds to his couldn't care less attitude and now his son Gavin (Ben Miller) has organised a posh dinner for 215 - that many for a long haired non-conformist?

The humour is filtered through a storyline that keeps losing credibility. The young ones are the stars. The adults seldom make it past small talk. The Scottish Tourist Board must have had influence over the locations because everywhere you look there's a loch, a mountain, beautiful sky.

Connolly could play Grandpa in his sleep which he does most of the time. The kids are good - they have the best lines. Tennant is resting and Pike treads water. Miller, remembered fondly from Death In Paradise, compromises his talent in a nothing role.

Co-writer/director Andy Hamilton is a funny guy. What happened here? An off day?