Hands down, the most powerful trend to emerge from London’s shows last season was its embrace of sustainability — not just as a hashtag or easy talking point, but as a revolution in thinking that united an entirely new generation of progressive, responsibly-minded designers. Five months on, you’d have thought there’d have been little by the way of additional change. But it has. After several years when the industry often seemed to offer little more than lip service, AW20 will be remembered as the season British fashion took sustainability mainstream.

‘In the global marketplace of the future,’ Roland Mouret’s show notes proclaimed, ‘the price of every product must tell the ecological truth.’ And whilst Mouret stayed true to his sinuous, sensuously tailored aesthetic, there was a shift to embrace what the designer described ‘values over trends’ — with a collection that celebrated sturdy longevity and signalled a move towards eco-friendly fabrics, the unveiling of partnerships with sustainable businesses Dear Frances, Bottletop and Arch & Hook and a promise that the label would go fully carbon-neutral within the year. Richard Malone started the week with a show that championed plant-based dyes, repurposed leathers and jewellery, and regenerated ocean waste — and ended it by winning the Woolmark Prize. And Ancuta Sarca’s imaginative reinventions of deadstock Nike trainers as hybridised new footwear forms provided one of the standout moments at Fashion East.

For others, the week offered a platform to make a statement without staging an actual show. Anya Hindmarch, whose spectacular presentations were until recently of the schedule’s highlights, closed all her London stores and filled them with 90,000 plastic bottles — a stark visual reminder of the world’s consumption rate (and a segue to her forthcoming bag collection, made from recycled bottles and windscreens.) Mulberry traded the runway for an in-store celebration of the craftsmen at its carbon-neutral Somerset factory. Vivienne Westwood and Andreas Kroenthaler took over the Serpentine Gallery with an event that was half-presentation, half-protest; ‘WALK THE WALK OR SHUT UP’, one banner cheerfully proclaimed. Osman Yousefzada partnered with Eco-Age to present a film exploring the fashion industry’s global impact. Iceberg teamed up with the BFC, MTV and River Island to launch a new sustainable design competition. Alexander McQueen’s Sarah Burton announced a giveaway with a difference — the opening of the label’s vast archive of leftover fabrics and their distribution to fashion colleges' students across the UK.

Of course, as protest group Extinction Rebellion pointed out in their demonstration outside the British Fashion Council’s main venue, the most sustainable course of action would be to have no fashion week at all. Katharine Hamnett was LFW’s brightest star in the Eighties and early Nineties, but her fight to make the industry take responsibility made her a near outcast; although her label is still active, she hasn’t shown on the runway since 2004. Christopher Raeburn, who’s built an internationally successful (and ethical) label, hasn’t shown on the runway for a year. At almost every show I went to across the week, audience members were talking of little else. Will the international fashion schedule survive? If it does, in what form? And — when it comes down to it — should it? Copenhagen announced plans to transform its fashion week into an advocacy platform and set a 3-year deadline for participating brands to meet 17 sustainability targets. Stockholm cancelled its event entirely last season. London, it’s your move.