THERE'S every reason to believe — if we turn a blind eye to Mr and Mrs Trump’s rather depressing union — that a significant difference in age between two people is no particular hindrance to an enduring and happy relationship.

It’s the thesis of Martin Sherman’s play, directed by Sean Mathias, about the tribulations of intergenerational love. In it Rufus (Ben Allen), a twenty-something young professional struggling with bipolar disorder, pleads with Beau (Jonathan Hyde), a sixty-something pianist from the Deep South in the US, not to forget about him after the hasty tryst they arranged online.

Indeed, he’d like them to spend more time together and perhaps even embark upon a relationship. But Beau has his doubts: “You wanted a daddy,” he protests to Rufus, “but soon you’ll have a grandaddy.”