According to the composer, "On behalf of the Scottish people the work craves absolution and offers Isobel Gowdie the mercy and humanity that was denied her in the last days of her life.

Further successes have included his second opera The Sacrifice, commissioned by Welsh National Opera, Autumn 2007, which won a Royal Philharmonic Society Award, and the St John Passion jointly commissioned by the London Symphony Orchestra and Boston Symphony Orchestra[7] and conducted by Sir Colin Davis at its world premiere in April 2008.

This central strand of his life and compositions was marked by the BBC Symphony Orchestra in early 2005, with a survey of his music entitled From Darkness into Light.

MacMillan and his wife are lay Dominicans, and he has collaborated with Michael Symmons Roberts, a Catholic poet, and also Rowan Williams, the Archbishop of Canterbury.

[10] Perhaps his most political work is Cantos Sagrados (1990), a setting of Latin American poetry by Ariel Dorfman and Ana Maria Mendoza, combining elements of liberation theology with more conventional religious texts.

MacMillan has explicitly stated that his aim in writing this work was to emphasise 'a deeper solidarity with the poor of that subcontinent' in the context of political repression.

He was also commissioned to write a setting of the text Tu es Petrus (Matthew 16:18) for the Pope's entry at mass at Westminster Cathedral on 18 September.

Sundogs, a large-scale work for a cappella choir, also using text by Symmons Roberts, was premiered by the Indiana University Contemporary Vocal Ensemble in August 2006.