At first glance, Mark Lanegan and Isobel Campbell appear more like mismatched lonely hearts than a Mercury Prize-nominated partnership: sensitive Scot seeks brooding US-grunger for long-distance love and nights of torment.

And up until Campbell melted the frosty De La Warr atmosphere with her comparing of Lanegan’s grisly murmurs to Elvis, the duo, dressed all in black and hidden in the shadows, seemed to agree.

An ocean may separate Lanegan’s LA from Campbell’s Glasgow but there are light-years between their musical heritage. Campbell was the whisper behind Belle And Sebastian, Lanegan the gravel and grit that led the Screaming Trees.

But theirs is a chemistry that works.

They opened with Seafaring Song from sophomore effort Sunday At Devil Dirt and, as Campbell’s Scottish twang fought to escape, and Lanegan dragged his baritone through beaten-up truck stops and straw-filled dust bowls, the frisson between them unfurled to reveal a partnership as awkward and captivating as that of Lee Hazlewood and Nancy Sinatra.

By the time they’d reached the Campbell-penned The Flame That Burns, a rattling Tom Waits-style strut, written about Lanegan’s battle with the demons of addiction, Campbell had revealed a character at odds with the softer-than-silk soul her skin might suggest.

The Ballad Of Broken Seas, title track from the 2005 Mercury Music Prize- nominated album, was sung under a solitary blue spotlight by Lanegan and is a guarded tale of death, loss and redundancy.

Who Built The Road, which evokes the taut landscapes of American novelist Tennesse Williams’ work, was introverted and ghostlike.

On the road to promote a six-track EP of out-takes entitled Keep Me In Mind Sweetheart, which was released in November, the pair finished with a ragtime version of Hank Williams’ Ramblin’ Man, before slipping away as innocuously as they had arrived.