THE main thrust of Mike Bartlett’s deliciously entertaining play hangs on the notion that the country could be brought to the brink of civil war over the monarch’s refusal to sign a government bill.

One thing leads to another and before you can whisper the dread word ‘treason’ we see the king of England dissolving Parliament much like his predecessor and namesake in the 17th century.

The Queen is dead. Long live the… what exactly? Well, what we have here is a man who not only speaks his mind but faithfully obeys his conscience. It’s a hopeless combination and chillingly believable, too.

Bartlett’s piece insists that history does indeed repeat itself so this is basically a re-run of 1642 when the people’s representatives were dismissed and left for their homes to prepare for war.

Robert Powell as Charles summons all his emotional strength to deliver a compelling portrayal of a man caught between a rock and a hard place as he teeters on a constitutional chasm.

However, the premise that the man and woman on the Clapham omnibus would actually risk everything in a revolution triggered by attacks on Press freedom is, of course, laughably fanciful.

Revolution might well be triggered by rises in the price of beer and burgers, perhaps – but not over questions of editorial freedom, about which very few give a hoot.

Jennifer Bryden impresses as Kate Middleton, whom she bizarrely endows with an almost Churchillian command of the English language, although Richard Glaves’ Prince Harry is certainly not as dumb in real life as the writer would have us believe.

Elsewhere, Tim Treloar’s Kinnock-esque prime minister is a Welsh windbag that blows from hot to cold, while the opposition Tory leader suppurates with insincerity, thanks to Giles Taylor’s slimily persuasive talents.

But be warned. The one we need to watch is Prince William (Ben Righton), who may well be the deadliest snake lurking in the Highgrove wildflower meadow grass.

King Charles III runs until Saturday (November 7).

John Phillpott