You Write The Reviews: The Pilgrim's Progress, Sadler's Wells, London

This year is a wonderful opportunity to reflect on the works of the composer Ralph Vaughan Williams, 50 years after his death. Packed concert schedules allow us to reassess the "cow pat" composer (or, according to Classic FM's polls, Britons' favourite composer). The culmination of these celebrations is the Pioneering Pilgrim series by the Philharmonia under the conductor Richard Hickox, which includes all nine symphonies and The Pilgrim's Progress, the greatest, most complex and the least stageable of Vaughan Williams's operas.

Vaughan Williams was much taken by Bunyan's tale. Although a "Christian agnostic" himself, he spent a good deal of his life crafting an opera around it. The Pilgrim's Progress distils the essence of the composer's development over the first half of the 20th century. But there have been relatively few operatic performances of it, since directors struggle with what Vaughan Williams himself termed a "morality", rather than an opera. So we are left with infrequent "semi-staged" performances to bring the work to life.

"Semi-staged" can mean many things, but rarely can it have meant so rich a conveyance of the essence of the story as it did here. Under David Edwards's imaginative direction, with minimal props and the orchestra and chorus ranged behind them, the performers brought out the inner meaning and emotional richness of Bunyan's allegory. Orchestra and chorus were in excellent form, seeming to relish the rare opportunity to get to grips with this work.

As the Pilgrim, Roderick Williams was a revelation, offering a light yet round sound and conveying in depth the emotional trajectory of the Pilgrim's journey. A starry cast included James Gilchrist, Robert Hayward and Gidon Saks, who relished parts as Apollyon and Lord Hate-Good. Gilchrist's voice was sweet and clear, and as Bunyan, Neil Davies delivered a clear and impassioned performance, if sometimes a little overwhelmed by the size of the orchestral forces behind him.

After the interval, Sarah Fox, along with Pamela Helen Stephen and Sarah Tynan, had great fun in Vanity Fair, which was realised in a paparazzi-filled market place where the Philharmonia Voices revelled in their love of Mammon, before Williams sang his heart out as he arrived at the celestial city. The only minor downside of this rare and intelligent performance was the rush with which Hickox finished the journey.

Will we ever see a fully staged Pilgrim's Progress? Perhaps Vaughan Williams would have been content with semi-staged performances as true to the soul of his "morality" as this one.