Harry Potter and the Cursed Child writer Jack Thorne and director John Tiffany swerve into kitchen sink drama with The End of History, a nicely-judged skid through the 20 years from Blair to Brexit in one bantering Berkshire household.

The provincial setting, the practical kitchen, the french windows are a marvellous throwback to seventies comedy. The badly cooked dinner (it could be Wendy Craig in Butterflies) and the skittish mother are equally deceptive. Form does not follow function and the play is infinitely cleverer than its superficial start.

There is something Weasley, or weaselly, about this family though: parents Lesley Sharp and David Morrissey are warm and witty, but the three siblings – Sam Swainsbury (straying not too far from his character in BBC2’s outstanding Mum), Kate O’Flynn and their afterthought gay brother are differently discontented with each other and with their parents.

This is a look back in unfocused anger.

They voice their internal monologues clearly but with so many different standpoints, the interactive dialogue doesn’t fly so well, except in scenes with Swainsbury’s posh girlfriend – a coolly smart Zoe Boyle – who the socialist parents are oddly anxious to please and flatter.

Although there’s no interval, three acts each end with a dramatic-to-melodramatic reveal and a ten-year time shift. It’s structurally clever, but there’s also some predictability.  After the most severe of these, Morrissey delivers a terrific speech which stops the laughter and has the audience completely rapt – a rare moment of superb theatre.

Finally, with admirable authorial restraint, the conclusion is cathartic but not redemptive.

There’s continual commentary on politics, voiced mostly by Sharp’s perfectly-observed character who is passionate about change and social justice.  And this may be the clue to how Thorne’s work stands apart from routine comedies of manners.

Death of a Salesman, another well-written domestic drama with disillusioned parents and angry children, is an anthem for the failed legacy of the American Dream.

The End of History may be an anthem for the failed legacy of Tony Blair.

until August 10