The Purcell Room hosted the UK première of Barry Guy's The Blue Shroud, released on Intakt Records - a really substantial work for 14-piece ensemble, forming a tribute to Picasso's great anti-war painting from the Spanish Civil War, Guernica. The composition was CD length at around 77 minutes, with the poem Symbols Of Guernica by Irish poet Kerry Hardie providing the structure - she read it at the start of the London performance, while the painting was projected onto the back of the stage.

The pan-European ensemble featured violinist Maya Homburger, Greek vocalist Savina Yannatou, Spanish pianist Agustí Fernandez, Irish guitarist and composer Benjamin Dwyer and Swedish saxophonist Per "Texas" Johansson. Other members were **** Paccoud (viola), Percy Pursglove (trumpet), Michael Niesemann (alto sax/oboe), Torben Snekkestad (soprano/tenor), Julius Gabriel (baritone/soprano), Marc Unternährer (tuba), Ramón López and Lucas Niggli (percussion). Guy directed, and played bass.

It's a stylistically convincing multi-genre work, with fluid transitions between baroque, Spanish, free jazz and big-band jazz styles. There's a Spanish inflection through Spanish acoustic guitar, free-jazz squalls, baroque passages that are more than quotation and pastiche, led by Maya Homburger. The vocalist ranges from free vocalising to spoken passages. Torben Snekkestad plays trumpet and soprano sax and towards the end, both together! It turns out it's a reed trumpet, and Snekkestad explains by email that this unusual instrument was pioneered by Eddie Harris in the late 60s on his album Free Speech, as here, it sounded surprisingly close to a conventional trumpet.

Other highlights included an amazing passage with scurrying percussion and strings; a free melée that ended abruptly, dissolving into a liquid, fruity solo tuba with multiphonics; and an explosive solo from Benjamin Dwyer on Spanish guitar. Guy is a musical force of nature, and - I reckon - one of the great jazz composers, a definitive
line-up being: Morton, Ellington, Monk, Evans, Russell, Bley, Guy. In fact his influences are broader than jazz, but are mostly jazz-based.

Have you ever wondered what goes into a performance? For some it might just be a quick run through of familiar standards, while for free improvisers any prep at all might be anathema. But for a large ensemble rehearsal is pretty much essential. Even more so when it comprises 14 musicians from nine countries who don't get together on a regular basis, as is the case with bassist Barry Guy's Blue Shroud Band.

In August Guy took advantage of a festival booking which fell through to rehearse the Band for two other upcoming festival appearances at the Frankfurt Alte Oper and the 2019 London Jazz Festival. While prestigious, such performances typically set aside only minimal rehearsal time and a soundcheck. While part of the group's DNA is it's gathering of accomplished sight readers who are conversant not only in jazz/improv, but also baroque music, there's still a need to refresh. Especially as the band last played its titular work, "The Blue Shroud," back in October 2017 in Essen, Germany. And in addition there was also new member, tubaist Marc Unternährer to absorb this time round.

But this was no ordinary practice. As well as running through the music, this was to be a key part of a film documenting "The Blue Shroud." The idea originated with Dublin-based filmmaker Jonathan Creasy, who also recommended using the historic Aghavannagh Barracks set high in the Wicklow Mountains of Ireland as the backdrop for the exercise. There was something poetic about making a documentary about a work dealing with the repercussions of war in a location so redolent of Irish history: a former military barracks built by the British to suppress the Irish rebels led by Michael Dwyer, a distant relative of the BSB's guitarist Ben Dwyer.

"The Blue Shroud" is deserving of such attention. The 70-minute plus work is one of the crowning achievements of the Englishman's career, uniting as it does the distinct strands of his work in Baroque classical, contemporary new music, jazz and free improvisation. It's a work founded on contrasts and juxtapositions, a bit like Guy's bass style writ large. He takes as his inspiration three interlinked themes, the Spanish Civil War atrocity at Guernica, Picasso's masterpiece of the same name, and the titular blue awning hung over a tapestry of that painting which was the backdrop when US Secretary of State Colin Powell presented the case for the invasion of Iraq at the UN Building in New York in 2003.

The concept sprang from discussions with Irish poet Kerry Hardie, whose words both provided a text and suggested possibilities for structure and diverse types of improvisation. To offset the resultant spiky improv and dense ensembles Guy co-opts some of the loveliest melodies ever written, creating settings for extracts from H.I.F. Biber's "Mystery Sonatas" and the "Agnus Dei" from J.S. Bach's "B minor Mass." In this circumstance, Guy uses these reimaginings to signify humanity's indomitable resilience in the face of suffering and ultimately hope.

For the rehearsal, the musicians were arranged in a semicircle in the tower of the Barracks with Guy the focal point. The combination of a fog machine and bright stage lights generated an extraordinary atmosphere in the room for the filming. Hardie came to the first session, and recited her poem to further reinforce the mood. Then Guy ran through the entire score bar by bar, working to achieve the desired impact. The repeated passes at the material allowed consideration of the complexity, detail and richness of voicings -"hear subtones from saxophones" -which might pass a listener by in the blur of the concert situation.

With similar attention to detail Guy instructed drummers Ramon Lopez and Lucas Niggli on what he was seeking from their rustling shell percussion: "I'd like it to be really kind of ominous." And it was, transmitting a hint of subdued threat, like an intruder crunching on the gravel outside your window. Guy's explanations brought various parts of the charts to ever more vivid life: "This is weird surreal theater. You've really changed personality here."

There was a palpable sense of camaraderie in the air. This was clearly more than a gig for all concerned. In another example of the democratic ethos Guy promoted, various members stepped in to cue particular sections, especially when Guy himself was busy playing. It was also manifest in how the musicians offered ideas as to how to make things work even better.

One of the highlights of the piece comes when the band breaks into a funky waltz powered by drummer Niggli's crisp articulations, which provides the context for Michael Niesemann's impassioned alto saxophone soaring through and above the surging orchestral vamp. As Niggli described it: "We stay super cool while he goes nuts." At this point, Lopez proposed adding a triplet motif on his hihat to emphasize the counter riffing of trumpeter Percy Pursglove, tubaist Unternährer and the strings during the jazzy swing. They tried it a co...