Holed up in a trailer in the eye of an Icelandic storm, with the wind howling and the temperature plummeting, and the ice sheets shifting beneath their feet, two thespians with history trade insults and reminiscences as they prepare to strut and fret their hour upon the sound stage of the seventh instalment of a second-rate sci-fi fantasy called Vulcan VII.

Seventh time lucky, thinks the persistent director and shrill producer, before the former breaks his arm when a snow plough plunges into a ravine and the latter suffers a nervous breakdown when everything which could go wrong does go wrong.

In the melancholic blue corner, Hugh “bit part” Delavois (Nigel Planer) whose stuttering career is on the rise thanks to a series of Upstairs Downstairs-type roles in which he specialises in playing The Butler. In this case, butler to the eponymous Vulcan. With a handful of lines and a foot in the door, it gives him one last inkling of an opportunity to make it after thespian number two pushed a custard pie in his face during a prestigious lunch with Alan Bennett. A viral fall from grace which earned him the nickname Custard Man.

In the bloodshot red corner, Gary Savage by name savage by nature (Adrian Edmondson) whose falling star is imploding after going from Scorsese’s go-to maniac to appearing in an advert for washing up liquid. No wonder he’s hit rock bottom, hit the bottle and hit upon every piece of skirt that walks his way. “Have we had sex?” he asks the tireless runner Leela (Lois Chimimba). “I’m not trying to push the boundary,” he explains. “I’m just trying to find out where it is.”

Embittered characters and perilous plot established, writers Adrian Edmondson and Nigel Planer, together with SoHo Theatre artistic director Steve Marmion, steer the RMS Don’t Panic through the iceberg-strewn waters of the business known as show. The humour is constant, though more chuckle than belly-laugh-inducing. The playing is fast-paced and wonderfully-timed (Planer playing the icy droll to Edmondson’s fiery diva).

And though it might not scale the comedic heights or plumb the dramatic depths which it teeters on the brink of delivering (talk of the demon drink and despairing lows hook the audience more than the whiplash one-liners – “marriage is like colonic irrigation: you can do without it”), the play provokes ripples of laughter for nigh on two hours. Unlike Simon Higlett’s tilting set which makes a big splash as it nosedives into the deep.

Peter Callaghan