FOR half a century or more, "King's" has meant only one thing in musical circles: the choir of King's College, Cambridge.

But when it ventures out of Cambridge, it is more likely to be found overseas than at home. So its visit on Thursday promised something rich and rare. It delivered on both counts.

Music composed in the 40 years before the English Reformation finds its way into cathedral repertories all too infrequently.

In truth, only world-class choirs can handle its often lavish counterpoint. King's, for example.

Stephen Cleobury this year celebrating 25 years as the choir's director, constructed his programme cleverly, using pairs of motets to the same words by different composers, and contrasting Glorias from two Taverner masses, all centred on "regal" pieces by Hacomplaynt and Fayrfax. Thus Taverner's gentle, high-voice Audivi Vocem preceded Tallis's darker version for men only.

The thrilling Alleluias of Tallis's Dum Transisset Sabbatum made an exciting finale, picking up where Taverner's more restrained account, at the very start, had left off. Some of the solo work in Hacomplaynt's tricky Salve Regina was self-effacing to the point of inaudibility, but the trebles sustained a creamy aura, even through the more virile passages of the Glorias.

The most telling flavour of a riveting evening was provided by the plainsong introductions and interludes, fluid and unpretentious. Tallis's hymn O Nata Lux made an ideal encore, its final phrase repeated in an exquisite pianissimo.