It may be cold inside, but there's nowt so warm as folk

, The Forum, London

"Glad to see you've kept yer coats on," says Billy, when he gets on the stage tonight. "Has someone left a door open?" Ah, the good old Forum; my second visit in a week and the boiler's still busted. Maybe the management thought, well, it's a full house, it'll warm up. Maybe they thought, Bragg fans - used to hardship. Whatever, it stayed relentlessly freezing. Might as well have done the show under the stars.

"Glad to see you've kept yer coats on," says Billy, when he gets on the stage tonight. "Has someone left a door open?" Ah, the good old Forum; my second visit in a week and the boiler's still busted. Maybe the management thought, well, it's a full house, it'll warm up. Maybe they thought, Bragg fans - used to hardship. Whatever, it stayed relentlessly freezing. Might as well have done the show under the stars.

Kate Rusby had the worst of it, playing to a trickling-in audience and having mistakenly worn a vest top over her trousers. She didn't complain (a 26-year-old from Barnsley - used to the cold, obviously), though between songs she shook her fretting hand to stop her fingers seizing up.

Rusby is one of the prime exponents of English traditional singing, alternating 300-year-old songs with some of her own, which fit perfectly beside them; her voice is angelic, her playing resonant. She appeared with one accompanist who hopped from violin to flute and sitar and, in a smaller hall, she would have been magical. Still was, in a way, chucking back her curls to tell us about the numbers - "I've changed this to mek it a bit happier. Bit of water and soom nice flowers in this woon," she explained, before delivering "The Fairest of all Yarrow", which is mesmerising and languid, old England made new. There's also "Cow Song", about a cow and a lusty milkmaid, which somewhere along the line involves a chap's trousers falling down.

All the way through, however, the audience kept up its own clearly vital conversations, which would've been less irritating if many of them weren't happening 2ft from the stage. The haunting lullaby "Sho Heen", Rusby imploring, "Why has my angel gone from me?" was almost drowned out by a couple roaring about their faulty relationship. "Thanks to Billy Bragg and the Blokes for lettin' us be their friends," said Kate, at the end. "You deserve better than this, love," someone near me murmured, accurately.

Mr Bragg, of course, can do no wrong with his fans, who'd cheer if he sang his shopping list. Tonight, however, there was a desultory tone to proceedings. Maybe he's complacent: Bragg currently knows more fame than he's ever had, riding a tsunami-sized wave of it in the States, where "Mermaid Avenue", his fine tribute to Woody Guthrie, has won a Grammy. Back in the old country, he's just had a road, Bragg Close in Dagenham, named after him. Or the problem could be that he's promoting Reaching To The Converted, a collection of rarities and b-sides that, when you hear them, you know were b-sides for a reason. In keeping with their flavour (anyone still got their Anti-Nazi League badge?), tonight was huge on polemic. Coming up to date, Bill had much to say about Marks & Spencer using cheap Asian labour, much to say about Kosovo, and it's to his credit that he's so passionate (Guthrie's "All You Fascists Are Bound to Lose" was a stonker, hammered out in dubby Clash style). He made good comments, too, on our climate of overwork ("Used to sing songs about miners and dockworkers. Now it's all about someone in a call centre in the Fens"), delivering a new song, "Saint Monday", in honour of cloth-workers told they could only have time off on a saint's day, so they nominated one. Of the secular stuff, "Sulk" got everyone going ("Why do I hide whenever you show up?/You know your moods make me want to frow up/Why don't you bloody well grow up?/You just sulk...") and "Accident Waiting to Happen" never fails; but much of the rest, including a lacklustre Faces cover, felt like filler. I'd taken along someone I'd hoped to convince about the wonder of Billy. After, he bought me a compensatory drink and I sat, like someone whose team didn't score, and sulked.