Set on the eve of the 1929 Wall Street Crash, Stephen Sondheim’s first-ever musical, transfers direct from its Jermyn Street Theatre sell-out. Written in 1955 (but first performed only in 1997), it’s remarkably prescient. Dodgy financiers, bad dates and delicious frocks, of course we all recognise our own lives.

Gene, a lazy get-rich-quick boy, is playing the stockmarket. Helena Blackman (runner-up behind Connie Fisher in BBC’s How Do You Solve a Problem like Maria?) is his down-to-earth girlfriend Helen. The young protagonists spend their time hopping between downtown Brooklyn and uptown Manhattan. We relish the romantic vulnerability (especially the male characters who can’t find a woman on Saturday night) and the jokes about the economy.

It’s hard to dismiss this witty, fundamentally optimistic piece performed by a vibrant cast. There are several very lovely torch songs. But, sorry, why should we care about these calllow twentysomethings? Why on earth would they let the selfish Gene off the hook?

We all understand about greed but this Saturday Night lacks stamina.If you’re a hard-core Sondheim obsessive you’ll love it as a fascinating piece of juvenilia. Otherwise it might just be an irritating 1930s episode of Friends.
Until 11 April. Information: www.saturdaynightmusical.com.