SUSPENSION of belief on an industrial scale is the key requirement when watching a Miss Marple whodunnit.

After all, we’re being asked to swallow the notion that there’s nothing unusual about an old woman wandering the countryside solving crimes and outwitting the police at every turn in the leafy lane.

Sadly, Judy Cornwell’s portrayal of the grand dame of detection is not the whole sleuth and nothing but the sleuth.

For not is it only hard to detect any real enthusiasm for the gig but on occasion she also appears to fluff her lines.

Thankfully, she comes out of her suspended animation during the obligatory confrontation with the guilty one, explaining her reasoning with such eloquence that it would appear that she has been paying attention all along.

Middle Ground Theatre Company’s stab at the Agatha Christie thriller is, however, otherwise first rate, the cast responding well to Michael Lunney’s subtle direction and keen eye for period detail.

Letitia Blacklock (Diane Fletcher) is the perfect host at this civilised gathering of well-bred potential killers, her gentlewoman persona neatly finding its counterpoint in the form of the gloriously batty Dora Bunner (Sarah Thomas) not that it will ultimately do the latter any good.

Meanwhile, Inspector Craddock (Tom Butcher) uncharacteristically displays much forbearance with the local geriatric amateur trying to queer his pitch, so it’s thank heavens for the fabulously over-the-top Mitzi the maid (Lydia Piechowiak) who gets the laughs every time she thunders into view.

This piece is probably not your best Christie ‘starter pants’ Miss Marple mystery but on balance is still entertaining. It runs until Saturday (September 5).