Sounds New, Canterbury's contemporary music festival, has focused on postwar Polish work this year, culminating in a performance of Penderecki's St Luke Passion with forces from Poland conducted by the composer himself. Last heard in the UK at the 1982 Proms, this 1966 work put Penderecki on the international map as an angry, avant-gardist. At Canterbury, with Polish dignitaries in attendance, we were conscious of just what an establishment figure he has become.

As a religious-political statement, the work still arouses intense admiration. Its aim was to redefine the Bach-based tradition of passion music in the aftermath of mid-20th century genocide, and Penderecki's choice of a Latin text over the vernacular expressed a libertarian Catholic militancy in opposition to totalitarian thought. Though the work's harmonic palette no longer shocks, its moments of extreme violence remain profoundly unnerving. Paradoxically, it is the meditative sections that now convince us less and are strikingly prophetic of the conservatism of Penderecki's more recent music.

It would be impossible, however, to imagine it better performed. Everyone seemed to have the music ingrained in their systems; that most of the Warsaw Boys Choir sang without scores indicates a level of familiarity with a work considered until recently unsingable. Their adult counterparts - the Katowice City Singers and the Polish Radio Choir Krakow - delivered their music with articulate ferocity, while the soloists negotiated their formidable vocal lines with wonderful surety. The only flaw was the over-amplification of the reciter-evangelist Boris Carmeli. Penderecki, who conducted the National Polish Radio Symphony Orchestra with great dignity, was rewarded with a standing ovation.