Daytona (Theatre Royal Haymarket)

Here's a big new quiz question: who was the last living playwright to take a leading role in his own play on the West End stage? Emlyn Williams and Noël Coward did it all the time. And Alan Bennett appeared at the Queen's in his Single Spies double-bill 25 years ago.

When Oliver Cotton's deeply felt new play about an unlikely love triangle in Brooklyn, 1986, opened last July at the Park, Finsbury Park, the author was appearing in a play by Peter Nichols on Shaftesbury Avenue.

Now he's turned up, a jobbing support actor transformed, in his own cast (replacing the excellent, explosively gruff RSC stalwart, John Bowe) as the long absent brother of his ex-lover's husband at the Haymarket, for a West End transfer (again directed by David Grindley) that overturns all my fears and expectations: it's a marvellous, moving play not a whit dwarfed by its grandiose new surroundings.

In fact, the edges and currents are sharpened and deepened on a raked stage with functional design by Ben Stones. And Maureen Lipman and Harry Shearer – the voice of Mr Burns in The Simpsons, currently celebrated in the terrific new play that bears his name at the Almeida – renew their Park performances with interest.

"It's a marvellous, moving play not a whit dwarfed by its grandiose new surroundings"

Cotton as Billy has high-tailed it to Brooklyn from his holiday hotel in Daytona, Florida, where he's cornered a man he thinks is the Nazi war criminal who tormented him and his brother – Shearer's Joe – in a death camp. He's wearing a charity shop suit and a garish Hawaiian shirt, and he’s bearing cartons of take-away Chinese, not gifts.

He's been living in Ohio these last 30 years, having run off with his half of the family real estate business, changed his name, even lived "another life" like the SS officer has been doing. Meanwhile, Joe and Elli – they're the 70-something Zimmermans (like Bob Dylan) – have settled into old age as committed amateur ballroom dancers. Their elegant foxtrot book-ends the play. But a whole lot of skeletons are rattled en route.

These involve the European migration to the States during and after the war years; lost love in a Sliding Doors scenario, poignantly encapsulated in one of several vivid long speeches – and who, apart from David Hare, writes long speeches these days? – beautifully articulated by Lipman, quivering on the brink of split love-loyalty; and "what is so right about right"?

For whatever happened in Daytona might have been a false move, or even a wrong one, however righteous. Elli and Billy, in different ways, have been living a lie, and also the lie that binds them.

At the Park, Shearer's Joe was hung out to dry on the sidelines. The Haymarket re-focus suggests something altogether different: a life of real heroism, romantic and practical, that trumps the other two. And Cotton has written himself a two-reel role that could only be bettered in performance by Jeff Goldblum; and that's a compliment, as well as a helpful tip for the surely inevitable New York transfer.