Glorious! Duchess Theatre, London

Certainly, a fascinating play could be written about this daughter of a Pennsylvania banker who forbade her to sing in public and then left her the wealth that enabled her sing wherever she liked. Glorious! by Peter Quilter is not that work. Indeed, the humourless will say that it mirrors Foster Jenkins's own reverse-alchemy effect: it takes top-rate material and produces one duff note after another.

But, also like the singer, it is supremely good-natured and joyous as it dispenses gags that are so Are You Being Served? in style, the show could be subtitled Are You Being Serenaded?

Maureen Lipman is majestically on song (so to speak). Lobbing carnations into the audience or decked out in tulle, tinsel and wings as the Angel of Inspiration, she may have a smack of Dame Edna, but the essential difference is the beatific, touching sincerity with which this diva massacres the music. As with Don Quixote, there's magnificence in this degree of delusion. It was a gift, you feel, for a woman to be so pottily focused that she could shut out the noise of mocking laughter or interpret the pandemonium in the audience as the equivalent of Frank Sinatra's screaming bobby-soxers.

In Alan Strachan's witty, handsome production, Lipman is surrounded by first-rate comic talent. William Oxborrow is wonderfully droll as her young, gay accompanist who gives rise to a stream of laboured innuendo: Cole Porter, he's told, always comes to her concerts "with a huge bunch of pansies". And Josie Kidd is delicious as her ditzy socialite friend, Dorothy. Yes, Florence was a friend of Dorothy without being "a friend of Dorothy", - if you get my gist (nudge, nudge).

I think that an Alan Bennett-type monologue would be the best way of capturing the essence of Florence's delusion. But Quilter's revue-like ragbag of a piece has its depths too, as in the sad final sequence where you see the diva revolve in ravishment at sound of an authentically glorious voice - and it becomes poignantly palpable what she was hearing inside her own head when she sang.

To 29 April (0870 890 1103)