his compelling documentary takes its name from ‘Since Yesterday’, a 1984 synth-pop hit by Glasgow duo Strawberry Switchblade. As a voiceover from the film’s co-director Carla J. Easton tells us, it’s still the only song by a Scottish girl band to crack the UK Top 30. One half of the duo, Rose McDowall, points out that ‘Since Yesterday’ wasn’t the wistful love song that everyone thought, but actually a rather prophetic meditation on nuclear war. It’s a neat encapsulation of this film’s prevailing theme: talented female musicians being misunderstood and marginalised time and time again.

Co-directed by music video veteran Blair Young with Easton, a member of all-female four-piece TeenCanteen, Since Yesterday is an act of reclamation that doubles as an alternative history of Scottish rock, pop and punk. Easton sets out their stall at the start: while “female solo artists and female-fronted bands are remembered and celebrated in the history of Scottish music, there seems to be a lack of girl bands included”. To right this wrong, she and Young have filmed revealing new interviews with members of innovative but undervalued bands ranging from ’60s vocal harmony duo The McKinleys to ’90s pop-punkers Lung Leg.

Invariably, their memories are bittersweet. Jeanette Gallacher, the sole surviving McKinley, looks back fondly at their brief flash of fame when they opened for The Rolling Stones and The Beatles. The young John Lennon, apparently, was “a wee bit aloof”. But she also notes that at their supposed height, they were ripped off so badly by promoters that they spent her sister Sheila’s birthday in a one-room London flat with just enough money to pay for heating and a bag of chips. There’s so much rich detail throughout this documentary that it’s a shame we don’t spend longer with each band.

The music industry’s endemic sexism becomes even more glaring when numerous ’80s groups have their say. Melodic post-punk act The Twinsets are advised by record execs to become more like Bananarama, and when Sophisticated Boom Boom singer Libby McArthur finds out she’s expecting a baby, her ambitious band mates immediately replace her. Sadly, the patriarchy’s toxic grip touches just about everybody in this documentary. Glasgow indie crew The Hedrons, who performed at top festivals including T In The Park and Download in the late 2000s, recall being told that major labels are reluctant to sign them because a band member might “end up getting pregnant”.

The history of pop is littered with acts who should have been bigger. But this film feels vital because it highlights how each of these bands had the odds stacked against them – mainly because they were women, but also because they were based hundreds of miles from London.

Some of them came heartbreakingly close: His Latest Flame, a Glasgow combo who emerged from Sophisticated Boom Boom, look every inch the polished pop stars when they perform their soulful single ‘America Blue’ on a late-’80s chat show. Equal parts galling and enthralling, Since Yesterday will leave you wanting to dig into the discographies of these gallant girl bands who might have been queens.