Operatic murders are two a penny, but operatic murder mysteries are harder to come by - probably because those who write the operas cannot resist making their miscreants sing first about what they are going to do and why. So it is good to report that Tête-à-Tête's 10th anniversary production succeeds largely because of Iain Pears's libretto rather than despite it.

This mystery is a historical one. One evening, while Lord Dudley was off romancing Queen Elizabeth, his wife Amy broke her neck falling downstairs. Whether she fell, jumped or was pushed, the scandal meant Elizabeth's favourite never became her husband and the Queen's shadowy advisers retained their influence. Pears, wearing both his hats as novelist and scholar, defines the characters in lines that are singable and succinct, and leaves space for Philip Cashian's music to speak.

All of Bill Bankes-Jones's production takes place behind a gauze, which lends it the look and feel of an Elizabethan painting. The musicians of Chroma, conducted by Tim Murray, are placed to the sides. A living portrait of the queen watches from the back, her eyes following each character, though she has the grace to lower them when Andrew Rees's loud, foppish Dudley tells his wife his passions lie elsewhere.

Amy Carson is a little too delicate as Amy, but Roderick Earle's ruthless Walsingham and Robert Gildon's - weaselly Cecil are well characterised.

Cashian's music is at its best when most sparing; the penultimate scene, in which an ensemble is built from recollections of earlier speeches, goes on too long. Still, this otherwise pacey one-acter is something of which the company can be proud.