Every time Mike Westbrook records Glad Day – his much loved settings of William Blake for two solo voices, choir and ensemble – the instrumentation becomes smaller as the vision grows grander. True enough, those who value Westbrook as foremost a ‘jazz composer’ – many say Britain’s greatest – might regret the jettisoning of big-band splendour that fuelled his original grand design in 1980. A 1997 remake stripped the scoring back to three saxophones and rhythm section, and this new version, recorded live in 2008, reduces further: violin, accordion, acoustic bass and Westbrook’s piano now carry the weight of material once propped up by an Ellingtonian-size big band.

But, as Blake said, fire will find its form, and this Glad Day represents the perfect convergence of content and form. Violin, accordion and bass put you in mind of Kurt Weill or of Stravinsky’s Soldier’s Tale, and this playful fantasy of an imaginary folk group is a powerful one – a troupe of minstrels from Blake’s own time who have somehow managed to sneak back through a time portal to the modern age.

Vocalists Phil Minton and Kate Westbrook (Mike’s wife) have been with the project in all its various incarnations, and through their onstage personae Blake’s poetic imagery is reborn. Minton owns one of the most astonishing vocal instruments around. In ‘London Song’ his quivering, resonant bel canto injects the music with ecstatic exhilaration, a little danger even. On ‘Long John Brown and Little Mary Bell’ he lets rip with his trademark improvised, abstract yodelling vocalisations: an unshakable force of nature. Kate Westbrook has a jazz singer’s impulse for tonal inflection and rhythmic elasticity combined with the deportment of a great actress.

‘London Song’ begins with a representation of chaos: vocal whispers and muffled cries from the London College of Music’s Chamber Choir which meander urgently towards an anchoring tonality. Westbrook’s choral writing is stylistically apposite, pitching up somewhere between formal hymnody and hot gospel – ‘I see thy form’ subtlety acknowledges ‘Jerusalem’ while ‘The Tyger and the Lamb’ is kept merrily on the boil over Steve Berry’s brawny, swingy bass vamp. Billy Thompson’s extended violin solos are a joy throughout. Westbrook’s jazz roots are clear; and Blake’s images burn as bright as fire.