AND sometimes they are six, other times they are eight, but on Tuesday, the Ukulele Orchestra of Great Britain were the magnificent seven.

Six men, one woman and their four-stringed “bonsai guitars” make the most joyous music from a notoriously fickle instrument with a reputation for going out of tune.

Lined up in chairs in formal evening wear, they are indeed an orchestra in appearance but stealth and surprise are their musical weapons of choice, backed up banter that delights in laying false leads. Jazz, blues, Tarantino and Spaghetti western theme tunes, rock of assorted heaviness from Hawkwind to AC/DC, disco and electro anthems, even whistling, are all within their compass, and unlike most orchestras, they all sing lead vocals.

They announce a camp fire song, and it turns out to be the Sex Pistols’ Anarchy In The UK (“I use ukulele”), done in the style of The Wurzels but far more wittily. The Good, The Bad And The Ugly is both beautiful and extraordinary, while the new addition to the 2011 set list, Kraftwerk’s The Model, is both stern and humorous simultaneously.

The Undertones’ Teenage Kicks is the one golden nugget not to gain from the transition, but Gnarls Barkley’s Crazy and especially Chic’s Le Freak are gloriously light on their feet.

Most breathtaking of all is the reinvention of Formby’s ukulele anthem, Leaning On A Lamp Post, as a Russian folk song.

Brilliant musicianship, a wrong-footing choice of material and the smartest wit add up to a fabulous night of string-driven wonder.

The Ukulele Orchestra of Great Britain, Grand Opera House, York. Also playing tonight at 7.30pm. Box office: 0844 871 3024.