Nick Curtis

With ingenuous honesty, Ronnie Barker has admitted that he wrote this weak sob story about a lonely cleaner purely as a career-boosting vehicle for his actress daughter Charlotte (pictured). Now, nepotism is not entirely unknown in the theatre, but I've never before seen it used so openly or to such little effect.

Mum is one of those weepily manipulative monologues in which a sad woman itemises the small tragedies of her life until she is stripped of hope and dignity. In this case, the soliloquy is addressed to a dead mother, and has a couple of clumsy cameo roles wedged into it. It reveals Barker senior - comic hero and national treasure though he is - to be a very poor playwright, and it neither stretches nor flatters Barker junior. Charlotte, looking like a lumpier Imelda Staunton, plays Alison, a 36-year-old woman who can't accept that her Mum has vacated her old armchair forever.

Meandering around James King's dingy set, she tells of dead-end jobs and a dead soldier lover, an unaffectionate father and a loveless life in "godforsaken" Dalston.

The various moments showcasing Charlotte's supposed versatility (despair, rage, tap-dancing joy) are spaced out by banal observations about horoscopes and libraries. Her performance is awkward when alone on stage, and doesn't improve during the blundering appearances of Alison's spectral lover and father. The tragedies and cliches pile up, and the last cruel plot-twist is not a surprise, just the last straw. Dan Crawford's direction may be stiff, but the script is stricken with rigor mortis.

Charlotte Barker must wonder whether it's worth earning the resentment of every under-employed actress who doesn't have a famous father prepared to trade on his name and reputation for her sake. Ronnie Barker insists that Mum does not mark the end of his 10-year, self-imposed retirement, but is a one-off project to give Charlotte a paternal push.

I certainly hope that this is the last bit of theatrical piggy-backing that the Barkers embark on - that it's goodnight from her, and good-night (to playwriting) from him.

Mum