Hangmen (Wyndham’s Theatre)

Hanging used to be a spectator sport in the UK: crowds would gather to watch the guilty (or occasionally not-so-guilty) party as they were dropped to their deaths. But in Irish playwright Martin McDonagh's new black comedy – transferring to the West End from a sold out run at the Royal Court – it's a hangman we're here to see. And a second-rate one at that.

Suffering constant comparisons to Pierrepoint, who is known as the best hangman in Britain, Harry Wade (played by David Morrissey) at least holds the title of being the last hangman in Britain. It's the day hanging is to be abolished (as late as 1965 in this country) and Harry is holding court in his pub in Oldham (his second job). It's frequented by a group of down-and-out alcoholics, who only go there to drink because they're buying a beer from a legal killer. When a 'vaguely menacing' stranger from London arrives in their midst and orders a pint of mild and some peanuts, Harry's murderous past catches up with him and his day takes a turn or two for the worst.

McDonagh's first play in the UK since 2003's The Pillowman asks: Who'd be a hangman? It also questions how killing in the name of justice changes the way we value life. They are questions explored through the angry, straight-backed, laughable, bow-tied Harry, who is probably the last person you'd want there on your day of reckoning. They aren't questions lingered over, though; the play lives less through the way it grapples with the morality of capital punishment and more through the comedy in the left-field situation these Oldham folks find themselves in.

And with Hangmen, McDonagh truly finds a whole new dimension to the phrase gallows humour. This is a darkly funny new play that has an off-the-scale hit rate in terms of wicked one-liners. McDonagh also keeps us guessing masterfully and there's a genuine thrill in watching the way the plot twists and turns, until it leads to its gobsmackng denouement.

At Wyndham's Anna Fleischle's magnificent set – which transforms from a prison cell to a startlingly realistic pub, to a grimy café with more than a touch of magic – is very at home. The designs lose none of their drama and the set feels as expansive as it did at the Court. Andy Nyman replaces Reece Shearsmith as Sid, Harry's assistant and he is very good. He plays it less for the comedy and as a result he is more convincing as the man with a grudge and a flawed plan.

Morrissey gives an excellent, even-handed performance, managing to be both convinced of his own worth and entirely ridiculous at the same time. He delivers the humour with a dead-pan assurance. But it's Johnny Flynn who makes Hangmen such fun. He is a remarkable fit to the oddball Peter, giving a performance that is supremely uncomfortable to watch. It's a hilariously unpredictable turn that gives Hangmen its black heart.

Directed with capable hands by Matthew Dunster, Hangmen is one of the best shows in the West End at the moment: brutal, bizarre and blindingly funny.

Hangmen runs at Wyndham's Theatre until 5 March.