Billy Bragg, St George's, Bristol

You could call it preaching to the converted, but we all need a bit of remedial work from time to time. The Hope Not Hate tour, which concludes tonight with a special extra performance at Hackney Empire, represents Billy Bragg's response to electoral gains made by the British National Party, especially in Bragg's home town of Barking. It's a proper Popular Front job, backed by trades unions Unison, Amicus, RMT and the GMB, and commemorating the 70th anniversaries of the Spanish Civil War and the Battle of Cable Street (at which demonstrators repelled a march by Mosley's British Union of Fascists from the streets of the East End of London).

As the audience arrives at the hall they are badged and stickered by anti-racist groups and disabled workers protesting against the government's plan to close down Remploy. Once inside, they can browse a variety of stalls, contribute to the Justice For Kirsty (McColl) appeal, and stop to buy a Billy Bragg tea-towel or a signed copy of his new book about what it means to be British, The Progressive Patriot.

On stage, the enormous anti-fascist banner has had to be abandoned for the night, as there's nowhere to hang it over the Georgian church's Greek Revival reredos, but Billy describes it so well that it's as if we can see it anyway, fluttering in our mind's eye throughout the performance. As someone who likes the politics but has never been entirely convinced by the music, seeing Billy Bragg live for the first time was a revelation (although even fervent Braggophiles must admit he goes on a bit). But stop all the clocks: Billy Bragg can sing.

He'd warned us that he was going to have a go tonight, pointing to the mug of herbal tea he was drinking and commending its voice-enhancing qualities. But it still came as a shock when, given the right song and a slow enough tempo, he'd coax that adenoidal burr into a real killer instrument, hitting all the notes high or low, sliding into a falsetto croon, and turning Johnny Cash into the Thames Barrier twang of Johnny Clash.

Naturally enough, Bragg sings best on the most sensitive songs, which usually means those dealing with love, teenage lust or Vauxhall cars, little gems of social-realist observation such as "Must I Paint You a Picture" or "The Marriage", where you get a whole Loach/Garnett Play For Today in a three-minute vignette.

The show was all solo, electric guitar for the first set and mainly acoustic for the second. There were Billy Bragg songs, Woody Guthrie songs, and a bit of busking where Billy started on The Carpenters until he got bored and switched to a thrilling version of "That's Entertainment" by The Jam.

When it came, the big speech about fascism, the International Brigades (a plaque in whose honour Bragg had recently helped unveil with the 91-year-old trades unionist and veteran Jack Jones), and how towns like Barking can resist the rise of the BNP (resources, resources, resources), was stirring stuff. By the time he encored with "A New England", we could do most of the singing ourselves, though getting the chance to cheer the death of General Pinochet remained my highlight of the evening.

Billy Bragg plays the Hackney Empire, London E8, tonight (020 8985 2424)