Schoolgirls out dancing are not advised to respond to advances from strange men sporting lopsided haircuts and full makeup. However, when Philip Oakey recruited 17-year-olds Susan Ann Sulley and Joanne Catherall in Sheffield's Crazy Daisy nightclub in 1980, the resulting Human League lineup produced one of the most influential albums ever, 1981's Dare. "One day, all music will be made like this," the music press said of the League's synthesiser-only sound; here, Oakey explains they wanted to do something "that wasn't based in rock". With that sound still reverberating through acts from Ladytron to Calvin Harris, the band are replicating their masterpiece.

Dare's songs are still remarkably fresh and unusual, with Do Or Die even sounding like an early type of acid house. But the band have cleverly mixed futuristic visuals with images that reflect the grim Britain Dare was born in. The haunting starkness of Darkness is illustrated by the 1981 BBC test card. The Sound of the Crowd is accompanied by Thatcher-era minister Geoffrey Howe and a sheep.

Members have come and gone, as has Oakey's notorious barnet; having refused to employ an avant-garde wigmaker for this tour, the 52-year-old sports an ageless shaven-headed android look that complements the synthetic sound as perfectly as his lugubrious baritone. The Sheffield charm that endeared them to the British public endures. Oakey struggles to keep a straight face while holding a tiny 1980 vintage synth, and the 40-something "girls" produce gasps for wearing, unfeasibly, even shorter skirts than they did in 1981. Love Action and Don't You Want Me predictably bring the house down, but a succession of later, mostly lesser hits (with The Lebanon even employing - pah! - rock guitars) underline the difficulty faced after Dare: how do you follow perfection?

· At Lincoln University (01522 526090) tonight. Then touring.