Not to be confused with the TV series, Arrested Development are the band that rap forgot. Their 1992 debut 3 Years, 5 Months & 2 Days in the Life Of … sold 4m copies as fans and critics swooned over their earnest but impassioned political idealism and sunny pop choruses. However, the follow-up album bombed and the cheery hip-hop hippies were effectively driven from town by edgier, gun-toting gangsta rappers.

And yet, here they are, playing to packed crowds. AD’s absence may have enabled them to stockpile hip-hop cliches – there are so many commands to “Say oh-ohh”, “Put those arms in the air” etc that someone may end up in traction – but the half-forgotten Atlantans are greeted like homecoming heroes.

They may be more of a party band these days, but the idealism remains in songs that, beneath the funk and sugar, are laden with references to revolution and Malcolm X. One of the group’s new female singers wears a “Racism sucks” T-shirt and there’s a striking moment when the three frontpeople hold a raised fist salute for more than 30 seconds.

For all the 90s clunkiness of his moniker, DJ One Love makes a fine rapid-fire rapper. Tennessee, the band’s catchy No 1 song describing “climbing the trees my forefathers hung from” still sounds powerful, and the sweetly well-intentioned homelessness story Mr Wendal is as relevant as ever. Every arm in the house raises for the Sly Stone-inspired smash People Everyday, rapper Speech’s eyebrow-rocketing fantasy about seeing off naughty thugs who “disrespect my black queen, grabbing their crotches and being obscene”. The diminutive, bespectacled wordsmith makes an unlikely nemesis, but is touchingly humbled by the euphoric response to old and new material, and Arrested Development clearly still have more to offer than a glimpse of a hip-hop future that never happened.

• At Boardmasters festival, Newquay, 9 August