A deep red hue lights the stage. It is St George’s day and King Arthur’s Britons are about to fight the invading Saxons. Centre stage, four soloists – Saxon priests – are gathered to perform sacred rites to ensure their victory. To the left of the stage a harpsichord plucks out a tune above a bass viol and theorbo, whilst to the right a spotlight falls on Merlin, who relates the story.

Purcell’s semi-opera King Arthur tells the heroic tale of King Arthur’s repulsion of King Oswald’s Saxon invasion and the rescue of his lover Emmeline from Oswald’s clutches. No autograph manuscript exists of the piece, based on a text by John Dryden, and the wildly diverging sources that do exist leave obvious scope for interpretation and manipulation. Philip Pickett, director of the New London Consort and an eminent advocate of period performance, has taken the controversial decision to not only rearrange the order of pieces, refusing to stick rigidly to any single source, but to reconstruct “missing material” and construct an entire narration.

Any performance of period pieces invariably treads a fine line between the hunt for questionably attainable authenticity and the constructive creativity of the performers; however, it seems strange that such a staunch advocate of early music, who has taken the trouble to find a theorbo for the performance, would boldly add a commentary in the voice of Merlin. Pickett’s explanation is that the music is so integral to the action that it requires contextualisation – which Pickett has devised to provide a witty commentary delivered by actor Nicholas Le Prevost.

Lighting by Ace McCarron is used to effect the differentiation of the scenes in the absence of props, costume, or scenery. Different hues and pattern effects are used to create atmosphere and signal the shift from spotlit narration to ambient lit scenes. The decision to use a red laser dancing around the coving as a spirit in Act II was particularly inspired, but unfortunately seemed not to be noticed by the majority of the audience. Although it was clever, I was not always convinced that the differentiation provided by the lighting made up for the lack of costumes, scenery or images.

Despite my reservations about the juxtaposition of the old with the new, the authentic instrumentation with the lighting, the performance by the New London Consort was exemplary and these talented musicians lived up to their reputation for artistry and virtuosity. Anna Dennis’ depiction of the spirit Philidel was impressive, with her full and agile voice suiting the part well. Faye Newton and Penelope Appleyard’s voices as the Sirens sent to distract Arthur from his mission were well matched, and Appleyard, overpowered by Dennis in choruses, came into her own here. Unfortunately Adriana Festeu appeared to struggle in the lower register at times, while Joanne Lunn gave a consistently high calibre of performance. Similarly, countertenor Tim Travers Brown, tenor Andrew King and baritone Benjamin Bevan all executed their parts admirably.

Pickett’s aim to produce “carefully planned programmes designed to combine the very best in scholarship and entertainment” results in a sort of tussle between old and modern, the established and the new. Pickett seems to be trying to revive early music by drawing in a new, younger audience, and whilst this is admirable, it is important that the resulting material does not detract from the original. Admittedly, Merlin’s commentary got a good response from the audience and a fair few chuckles, but Pickett’s Purcell for the 21st century? I’m not convinced.