IF it's true that a performance can define its own context, then that is precisely what happened on Thursday night when Donald Runnicles, the BBC SSO, a quartet of distinguished soloists, and the National Youth Choir of Scotland gave a performance of Mozart's Requiem that, quite frankly, I found wholly convincing and profoundly moving:

a performance, in short, that completely blew me away.

The Requiem, of course, is a torso, and one that has been much touched up in its history. The latest version, an edition completed and prepared in 1996 by the irresistibly engaging musicologist and performer Robert Levin, was the subject of discussion before the concert. Everyone has a view, and I heard some of these views on Thursday.

But you know what? Donald Runnicles's performance set aside partisan views and established its own parameters of credibility. Obviously, Runnicles believes in Levin's new edition (he has recorded it). But this performance was packed with such dramatic and emotional power that it transcended any cerebral or polemical debate on the validity or veracity of this or that alteration.

And the core of the conviction with which this Requiem was delivered lay in the powerhouse performance of Christopher Bell's NYCoS, which I have heard in many forms and on many occasions, but never singing with such maturity, quality and authority. This was world-class singing, absolutely top-drawer performing from an ensemble at the top of its young game.

And what maturity, too, from cellist Alisa Weilerstein in a soulful account of Elgar's Cello Concerto that demonstrated how far she has travelled in the few years since her debut here.