The Impossible Gentlemen, Pizza Express Jazz Club Soho

Of the many challenges facing a contemporary jazz quartet, there are, perhaps, several more pressing than becoming a gentleman. For this extraordinary band, their conviction derives from the affection, respect and detail with which they synthesise such a breadth of jazz tradition.

Just arrived in London for the final leg of a tour to launch their second album Internationally Recognised Aliens, this first night of four at Pizza Express was an utterly compelling statement of that identity, spanning several genres of the contemporary jazz guitar.     

The gentlemen’s variety is immediately suggested by the contrasting backgrounds of the British pair who have composed the majority of the band’s music. Self-taught jazz fusion guitarist Mike Walker composes jointly with the serial academician Gwilym Simcock, with occasional contributions from American drummer Adam Nussbaum. Before they have so much as picked up an instrument, their music encompasses genres and continents.  

Unlike some of the explosive bands of the moment, these gentlemen don’t scream 'now'

The bass role is shared between veteran virtuoso Steve Swallow and, on this tour, the multi-talented bassist and producer Steve Rodby. When, like Rodby, you have more Grammys than you can count on the fingers of both hands, what else can you do but pick up your bass and make the softest, gentlest groove?

Generically, the gentlemen were most strongly influenced by jazz-rock and the blues, with funk and Latin jazz shading a couple of pieces, and Simcock’s composition "Barber Blues" - though structurally a 16-bar blues - dipping a toe into his classical training with an appreciation of American composer Samuel Barber. Walker’s fondness for programmatic pieces like the darkly comic "Willender’s Last Stand", meanwhile, about a tightrope walker blown to his death during his final retirement performance, lent the evening a prog-jazz flavour.

The individual players’ sounds were just as varied as the generic programme. Walker - whose palette of exquisite electronic sounds was perhaps the band’s most distinctive feature - delved deep into into the soul of the instrument, at home with both Frisell-like Americana and a driving rock beat. At times (for example during the encore, Nussbaum’s "Sure Would Baby"), he coaxed a wail from his guitar so intense it made the spine vibrate like his guitar string. Rodby and Nussbaum both gave superb solos, though much of the time their contribution was a gentle, teasing groove, Nussbaum often tapping the drum skin with his fingers. Simcock was everywhere, sometimes driving unobtrusively - the showy stuff was left to Walker, mostly - but always ensuring the harmonic lines of piano and guitar didn’t clash.

The group’s ambition encouraged technical innovation. Simcock sounded convincingly louche playing a Moog for the first time on this tour, while Rodby, used to playing more tightly composed pieces, was picking and mixing the notes with the liberated glee of a boy in a sweet shop.

Unlike some of the explosive bands of the moment, these gentlemen don’t scream "now": their roots in the history of the music are too deep for that. Their approach, formally quite traditional but brought to life with virtuosic musicianship, is infused throughout with a deep knowledge of and respect for jazz tradition. They ooze musical authority, and in that sense, they are gentlemen.

• The Impossible Gentlemen are at Pizza Express Jazz Club until 24 October, then at the Royal Welsh College of Music and Drama, Cardiff on 26 October