Kenneth Leighton’s and Frank Martin’s Masses begin almost identically, and for a time the similarities between them are so obvious that one would imagine Leighton already had a thorough acquaintanceship with the Swiss composer’s setting when he started work on his in 1964. Yet Peter Quantrill’s booklet note would seem to imply otherwise, and very quickly typical Leighton isms wipe away any lingering aromas of Frank Martin.

Those Leighton isms – driving, impulsive rhythms, highly energised chromaticisms, intensity built up through frequent repetitions of small musical cells, and that sense of continually building up polyphonic lines to some ecstatic climax – are fervently delivered by the gloriously robust King’s College London choir. Joseph Fort is clearly very much in his element with this music and drives his singers onwards with an almost hypnotic zeal.

There are two substantial points of departure between these two Mass settings. First, Leighton calls for a quartet of soloists. Mimi Doulton is the first to show herself in a powerful, forthright setting of the Gloria, and while the other three – Caitlin Goreing, William Hester and Joseph Edwards – easily match her full-throated presence, their very forward placing in the sound stage can seem a little overwhelming.

The second difference comes with the Credo, where Leighton added an organ part in an otherwise unaccompanied work. Played here by James Orford on the organ of the church of St John the Evangelist, Upper Norwood, London, this creates an appropriately rugged foundation for this fundamental expression of Christian faith. But quite why Leighton did this remains something of a mystery; as does the decision to close the disc with a highly atmospheric, plainchant infused organ piece by Jehan Alain originally intended to conclude not a Mass setting but the late-evening office of the church.

Magnificent as the Leighton work is, it does not really hold a candle to the Martin Mass, which remains, for me, one of the truly great choral works, the finest a cappella setting of the Mass of the 20th century. Similarly, despite their outstanding performance of the Leighton, there is a real sense of involvement about the choir’s singing in the Martin which is in an altogether different league. True, there are rough edges and a few coarse moments here (notably in the ‘Christe eleison’), but, above all, this is a performance of astonishing intensity and musicality. A powerfully moving interpretation of a powerfully moving work.