The Unthanks brought their UK tour in support of new album, Mount The Air, to a close in front of a sell out crowd at The Queen’s Hall in Edinburgh. Departing from tradition, not for the first time tonight, The Unthanks eschew the time-honoured format support band followed by main act. Instead, The Young Uns – a trio of acapella close harmony singers – open each of the two halves of the show. Beginning with a terrific version of Billy Bragg’s Between The Wars, the Young Uns win over the audience instantly with a combination of first class vocals and humour. “How could you not love The Young Uns?” asks Becky Unthank later, and I honestly can’t imagine anyone not doing so.

The Unthanks – ten of them in this current incarnation – file onto the stage and open with two tracks from the new album. Right from the outset it is clear that we are in for a very special evening. You can probably count on the fingers of two fingers the number of bands that have successfully incorporated a string quartet into their line up;The Unthanks are one of them and The Northumbrian Soul Orchestra – they’re not actually called that but they really should be – add a real depth to the sound and ensure that tracks like Feltin Lonin and Last Lullaby retain all the subtlety and intricacy of the recorded versions.

Two of the tracks on the new album top the ten minute mark and the band decide to only play one of them. As keyboard player and musical director, Adrian McNally, explains: “It’s not your attention span we’re worried about; it’s ours”. Mount The Air begins with a yearning trumpet figure that nods to Miles Davis’ Sketches Of Spain but swiftly moves on to explore other territories, building pace as it grows and culminating in a joyous clog dance from Rachel and Becky. Special mention, for her contributions here and throughout, has to go to trumpet and flugelhorn player, Victoria Rule, whose passion, power and purity of tone is truly outstanding.

Niopha Keegan, an integral Unthank on violin and vocals, has spent most of this evening hidden at the back of the string quartet. She comes to the front of the stage to feature her instrumental tribute to her late father, For Dad. The tune opens with an audio clip of a conversation between the three year old Niopha and her dad and a surreptitious glance around the hall reveals a mass outbreak of tear wiping and throatlump swallowing.

Folk music has always looked to the past whilst enshrining contemporary songs into the tradition. The Unthanks have done more than most in recent times to place mainstream songwriters in the folk catalogue, covering songs by artists such as Elvis Costello, Antony Hegarty and Robert Wyatt. Hegarty’s Spiralling and Out Of The Blue by Wyatt’s partner Alfreda Benge slip seamlessly into the set list. King Crimson’s Starless – a prog rock monster of growling bass, squealing sax and clattering drums in its original form – is transformed into a thing of dark beauty with Victoria’s trumpet shining at its core.

A reprise of Mount The Air and the title track of the previous studio album, Last, bring the performance, and the tour, to a triumphant end. Thanks, Unthanks and hurry back soon.