Performances, Wilton's Music Hall, London <!-- none onestar twostar threestar fourstar fivestar -->

Brian Friel gives the last word to music in his potent hybrid drama Performances, receiving its English premiere in a compelling production by Lou Stein at Wilton's Music Hall. This strange 70-minute event concludes with a thrilling account by the Brodsky Quartet of a movement from Intimate Letters, the second string quartet by Janacek. "You'd learn so much more by just listening to the music," Friel's Janacek tells a researcher. But the play is a deeply ambivalent piece and when we come to listen to the music, it is no longer possible to hear it innocently. At one level it does seem to transcend the preceding argument. It does not, however, cancel it out. Perhaps it's an illusion, but the emotional power of the performance seems to draw on the autobiographical considerations that the play sets before us.

The piece focuses on Janacek's passionate love for Kamila Stosslova, a married woman 44 years his junior whom he met in 1917. By the time the quartet was written by the 74-year-old composer, in the year before his death, shehad received more than 700 letters from her admirer. Friel approaches this relationship not through costume bio-drama but a contemporary debate about the relationship between life and art, muse and music, language and what can only be expressed by non-linguistic means.

Set in the composer's work room, the piece dramatises an imaginary interview between Janacek (Henry Goodman) and Rosamund Pike's earnest Anezka, a Czech graduate student working for a doctorate on the context of the second string quartet. Munching lettuce for his heart condition and doodling on the piano, Janacek combats her contention that his epistolary affair with Kamila constitutes "a textbook example of a great passion inspiring a great work of art".

He affronts her by suggesting that the Kamila to whom he wrote was his own convenient invention, a pretext for the outpouring of musical passion. What she was in her own right is, in a sense, immaterial. Listen to the music for the truth: "The people who huckster in words merely report on feeling. We speak feeling."

The piece is a bit too essay-like and yet, huckstering in words to scrupulous effect, it provides an unsettlingly powerful and self-questioning dramatic context for the Brodsky Quartet's sublimely searching account of the rending ardour of the concluding movement of Intimate Letters - a performance that, on its own, would be worth the price of admission.