George Bernard Shaw’s 1928 play “set in the future” may not have fared all that well in recent revivals involving Peter O’Toole and Penelope Keith (in separate versions) but Peter Hall’s hugely enjoyable production restores a timeless tension between monarchy and democratic government.

In the famous interlude, Janie Dee disports herself in mauve silk as the king’s mistress, Orinthia – a part first played by Edith Evans – with the consciousness of a goddess and the manners of a slut. She’s the safety valve in a royal marriage, the Camilla to the king’s Diana, the leg lock in a democratic embrace; and she wraps her calves lubriciously around his anointed head.

It’s uncanny, almost spooky, how the play suddenly throws back witty and timeless apercus. “Football and refreshments are all that the nation cares about now,” is one such remark, while no-one demurred much in Bath at the idea that the prime minister actually was the prime minister because he was good for nothing else.

As this beleaguered Labour leader - a character clearly based, and with ambiguous affection, on Ramsay MacDonald - James Laurenson offers an attractive mixture of grey-suited affability and bone-headed vanity, which sounds just about dead-on Gordon Brown to me.

The play is now revealed as a scintillating satirical vaudeville on how an intelligent monarchy might prosper in a less than intelligent people’s democracy (hilariously represented by Barry Stanton’s union-endorsed board of trade minister in a revolutionary red toga) and it’s instructive to see the ministers in full - “the overcrowded third class carriage of the cabinet” - assemble on red plush chairs, medals and honours intact.

Can they possibly be for real? Julia Swift’s squat, ginger-haired, fixed-grinning postmistress general is a dead little ringer for Hazel Blears, while Penny Bunton’s power-mistress general is an out-gay version of Jackie Smith with slightly better dress sense. None of this would matter two figs if not for the nagging satirical genius of Shaw’s writing.

It may be out of date but it still sticks like needles. The king threatens to abdicate and stand for a parliamentary seat in the royal borough of Windsor. Hall’s production, handsomely designed with muslin curtains and mottled panels by Christopher Woods, is a genuine rediscovery, and one of the best political theatre treats currently on offer.