It was proof of the power of radio. A desperate Roger Daltrey, spokesperson for the Teenage Cancer Trust, announced on Radio 5 Live that the mid-week slot of the charity gig‑fest was empty. So sandwiched between Antony and the Johnsons and Stereophonics the Albert Hall would be dark.

DJ Simon Mayo challenged his listeners to come up with a band who might be free. And faster than you could say real ale, Fairport Convention were contenders. The archetypal folk-rock band headlined the show, which was a night of folk with strong supporting musicians, all of whom played for free.

Eliza Carthy, taking the stage after feeding her baby in her first gig as a mother, played a fabulous comeback set fizzing with energy and high spirits. With a husky black velvet voice she cast a vocal spell and mixed it with her fiddle and cranky Tom Waits-style band. Her last song, a witty satire on car-crazy Britain, had the energy of an encore.

Kate Rusby reworked some songs from her first album Hourglass with sweet effect, backed by a 10-piece string ensemble. And Seth Lakeman delivered his punchy tight acoustic rocking folk with usual verve.

Fairport themselves revelled in being in the Albert Hall and two glories of their past, Sandy Denny and Richard Thompson, were celebrated in a stirring rendition of Who Knows Where the Time Goes? with guest vocalist Kellie While and a fine encore of the Thompson-penned Meet on the Ledge, Lakeman joining them in a liberated chorus of song. It was emotional, free and committed folk.