On Sunday 22nd April, over three hundred, mainly British enthusiasts crammed into the Sistine Chapel. Most had made the journey specially for the occasion. Some may possibly have used the event as an excuse for a happy weekend in Rome, but by late Sunday evening all realised that they had taken part in something extraordinary.

Sir James Macmillan is Scotland’s leading composer. He has long enjoyed a fruitful and mutually enjoyable relationship with The Sixteen and their director, Harry Christophers. So, with the benefit of hindsight, it is perhaps hardly surprising that Sir James should have written his setting of Jacopone da Todi’s ‘Stabat Mater’ for The Sixteen, arguably our greatest choral music ensemble. In doing so he was adding his name to a list of great composers, stretching back centuries, who have been moved by Jacopone’s poetic rendering of a mother’s agony at the ordeal of her crucified son.

The new work received its first performance in October 2016 at the Barbican and Cardinal Nicholls’s instant reaction was: “This must be performed at the Vatican.” So, last weekend The Sixteen and the Britten Sinfonia duly performed it there. You could almost touch the sense of anticipation amongst the audience, so thick was it on the air as they settled into their seats.

From the moment half the ensemble entered from the back of the Chapel singing Stabat Mater in plainsong, via what your technically unqualified reviewer was told are Berlioz pizzicatos, to the final quiet Amens, we realised we were experiencing something spiritual and sublime.

The atmosphere during the performance itself intensified. It was clear from what the performers said afterwards that they fully shared the excitement. To perform a work you know to be a masterpiece overlooked by the works of Perugino, Botticelli and Michelangelo might possibly take some beating in a musical career. No wonder they surpassed even their own high standards. The composer’s delight in the performance must have further validated their sense of satisfaction. Sir James is a quiet man, but, at the end, he was positively purring.

There had been little time for rehearsal in the Chapel itself and there had been what proved to be ill-founded rumours about the acoustics. However, the rehearsal time had been clearly enough and, as one of the performers said afterwards: “The acoustics were great: when you turned on the power, the hall could take it.”

You can download the performance, but sadly only part of the atmosphere will be transmitted through the ether. However, the evening was a tribute to the magic in so much of today’s British music.

It should also be a tribute to John Studzinski, the imaginative maecenas whose generosity made the whole venture possible. Private patrons can do things publicly funded bodies could never do. They can be quixotic in bringing ideas to fruition and to great effect. We owe Glyndebourne’s existence to such quixotry. In Studzinski’s case his patronage extends beyond putting on even the greatest concerts and many a British musical career owes him a large debt of gratitude.

He, Sir James, Harry Christophers, The Sixteen and, not least, the Britten Sinfonia deserve to bask in admiration.

Lord Salisbury is the chairman of Reaction