Originally published as a memoir in 1990, then dramatised in 1999, The Lady in the Van has the witty one-liners and acute observations we expect from Alan Bennett's satirical pen, even if the play never really gets out of third gear.

This true story of how an elderly bag lady came to live in her immobile home in Bennett's driveway in Camden Town for 15 years is really a series of incidents rather than a developing drama, probably better suited to the page than the stage. Nevertheless it has to be said that, despite the lack of dramatic momentum, this is highly entertaining stuff, where the comedy has a serious undertow.

The play is certainly not just a 'star vehicle' (Susan Hampshire here following in the footsteps of Maggie Smith, who created the title role), as it's really an examination of the awkward relationship between Miss Shepherd and Bennett himself. Or, rather, Bennett himselves because there are two embodiments of the author here: the narrator looking back on past events and the participant who is actually involved in them at the time.

It's a nice idea to have the doppelganger Bennetts interacting and often disagreeing, reflecting his ambivalent motives for tolerating Miss Shepherd's smelly and demanding presence for so long. Who is calling the shots, the kind (if passive) good samaritan or the detached observer who just wants raw material for his writing?

Susan Hampshire is very convincing as the aged and delusional Miss Shepherd, refusing to sentimentalise this frequently cantankerous if vulnerable woman, provoking both laughter and pity. The lady may be a tramp but her fierce independence of spirit commands some respect.

David Holt and Paul Bigley as the older and younger Alan Bennett respectively both give uncanny impersonations of the playwright, as the dynamic with Miss Shepherd swings back and forth between writer/muse and carer/dependant.

Antonia Pemberton as Bennett's Mam, whose Alzheimer's confines her to a nursing home, is a comic and touching parallel to his 'adoptive mother', who refuses to be bound by the welfare state.

Director Christopher Luscombe does what he can to keep the action moving, while Jonathan Fensom's set strikingly evokes the expanding chaos of Miss Shepherd's detritus. The show ends with the memorable image of her bright yellow Bedford van ascending to vehicular heaven in the flies.

- Neil Dowden (reviewed at the Richmond Theatre)