Here is a well-intentioned but baggy, unfocused and unsatisfying documentary about punk legends the Slits, which feels like an assemblage of footage that could have been shaped in a clearer and more interesting way. It is evidently coloured by the continuing sadness that followed the death of Ariane Daniela Forster, or Ari Up, in 2010, after the Slits had been enjoying a reformed renaissance.

Ari was the fiercely talented and committed German singer whose mother Nora married John Lydon – a remarkable fact that does not, in fact, clearly emerge from this film and might on its own cast light on an intriguing emotional dynamic within the punk scene.

When the Slits emerged on the scene in 1976, “girl bands” – and what a condescending phrase that is – were an exotic and scarcely tolerated rarity. They did not want to look pretty or sexy by male standards; they wanted to be tough and rock’n’roll – by male standards. There was an enormous amount of misogynist prejudice against them, although this was perhaps hardly noticed in the whirlwind of controversy and anarchy that punk conjured up in those years. It was, after all, a horribly violent culture.

An interview with bass player Tessa Pollitt reveals that one of the band was slashed with a knife by a man who shouted: “There’s a slit for you!” She adds, equably: “People love a fight. Don’t we all?” (Er … no?)

In the early 80s, the Slits experimented with new musical forms and had every claim to be considered a real influence. After the split, Viv Albertine became a respected author and Paloma Romero (or Palmolive) became a Christian and teacher. Sitting down and listening to their songs sorts the fans from the non-fans. Shoplifting and Typical Girls still throb with that Slits spirit.