Fionn Regan, University of London Union, London

Dark star of the plaid brigade

For a Dylanesque singer-songwriter, Fionn Regan certainly looks the part: the under-nourished sort of slightly-built that arouses maternal instincts even in men, with pipe-cleaner jeans supporting plaid shirt and harmonica-holder.

The bowl haircut's not quite up to Bob's bird's-nest tangle, but it has a certain charm of its own, blending as it does the simian sullenness of Ian Brown with the pageboy demureness of Princess Di. With a cherubic visage similar to Ron Sexsmith, he's every inch the modern wandering troubadour, with the classic combination of vulnerability and toughness.

Sidling on to the stage as if trying to enter a room unannounced, Regan opens his set with "Hey Rabbit" from his Mercury-nominated 2006 debut The End of History, his band joining in gradually as the song progresses, lending momentum to its animal imagery of rabbits and worms and "ideas [that] are like sparrows". But it's the following "House Detective" that kicks the set into gear, Regan swapping his Gibson acoustic for a Fender Telecaster and rattling the lines out against a "Maggie's Farm"-style electric rockabilly grind.

His band are dressed in various shades of thrift-shop Western, a motley parade of cowboy shirts and unorthodox neckwear, and they lend the bite required to push Regan's songs towards the edge. The drummer is particularly ear-catching: he may resemble Buddy Holly wearing a silver waistcoat, but he has an unusually thoughtful way of animating the material that recalls the great Jay Bellerose, with plenty of mallet work, and subtle touches underscoring the quieter passages of songs such as "Violent Demeanour".

The set is equally split between The End of History and its recent follow-up, The Shadow of an Empire, with the latter's tracks like "Coat Hook" and "Catacombs" displaying both a looser, more devil-may-care approach, reflecting his decision to "go electric", and a bitter lyrical flavour that's like the difference between dark chocolate and milk – "Catacombs", for instance, hinting at drug addiction and physical abuse, and "Violent Demeanour" with its depiction of mental illness.

Regan seems to be developing his own distinctive lyrical tics, which is a good thing, even ones as odd as fantasising about people as headgear, his offer to "wear you like a hood" in "The Underwood Typewriter" now reciprocated in "Coat Hook" with the desire to "let me be your pearl grey fedora". At least he seems to have got over the fascination with American authors evident on the earlier album, where "Put a Penny in the Slot" featured references to both Paul Auster and Saul Bellow, perhaps Regan's equivalent of T S Eliot and Ezra Pound fighting in the captain's tower.

He reverts to acoustic guitar for "Lines Written in Winter", a moving observation from the viewpoint of a homeless man sleeping rough beneath a bridge "like a comet in a dungeon". It's a song which probably wouldn't work as well without the band, its structure changing constantly, almost line to line, with Regan's delicate fingerpicking deftly tinted by the subtle accompaniment. As the applause dies down, he finally welcomes the audience with the brief but well-turned "How are you all keeping? Myself, up and down like a dumb waiter." It's characteristically cute, though perhaps too anachronistic for his younger fans to follow.

The rumbustious punk-folk rockabilly of "Protection Racket" and "Genocide Matinee", twin blasts of social critique couched in beatnik verbosity, kicks the set rowdily towards its climax, before Regan closes with the introspective "Lord Help My Poor Soul". He returns alone for an encore of his most famous song "Be Good or Be Gone", its generous warmth reciprocated by the audience as Regan backs away from the microphone and lets them sing the refrain back to him. "Ah, the E finally kicked in, then?" he quips as he departs, sharp as a tack, sly as a fox, slippery as an eel.