The new musical Killing Rasputin at the Bridewell is a disappointment. The lyricist is Kit Hesketh-Harvey, one half of the sophisticated cabaret act Kit and the Widow, and the composer is James McConnel, who has come up with a melodic and often darkly dramatic score.

The show follows the fortunes of the sinister Rasputin and the Russian aristocrat Felix Yusupov, who finally succeeded in bumping him off, and Hesketh-Harvey and McConnel have been working on it for more than five years.

Unfortunately, despite the evident talent on display here, I fear they have missed the boat. Killing Rasputin belongs to that glum tradition of portentous, humour-free musicals that became such a baffling success in the Eighties, the kind of show that made slitting your wrists seem an attractive option. I suspect, however, that the current taste is for wit, glitz and sex appeal, exactly the qualities Hesketh-Harvey is usually so adept at providing. Unfortunately he seems dourly determined to keep a straight face here, with endless agonising over love, religion, revolution and haemophilia.

The storyline is admirably clear, the songs are strong, and Ian Brown's spare production is powerfully acted and sung. But who needs two hours of miserable Ruskies? This is the kind of po-faced theatrical worthiness that Hesketh-Harvey would delight in sending up in his cabaret act, and the whole show betrays an alarming failure of his usual, highly developed sense of irony.