With Joe Lycett hosting, the eight remaining home sewers head back in time to the 1970s, attempting to revive the glamorous, rebellious and sometimes ridiculous style of the decade. This is more than a stroll down memory lane as they tackle the decade's most fiddly, floaty and anarchic garments.First up, judges Patrick Grant and Esme Young challenge the sewers to get their groove on with the trickiest pattern so far, flared jeans. Creating the perfect bell-bottomed trousers involves grappling with vintage machines, heavyweight fabrics and taking on such daunting technical hurdles as the zip fly and flat-felled seam, hopefully without getting in a flap. For the transformation challenge, fabric flies and anarchy rules as the sewers let rip with their imagination, turning t-shirts and tartan into provocative punk-inspired outfits in just 90 minutes.In the made to measure challenge the sewers take on their final icon of 70s fashion, the maxi dress. Working with sheer, slippery fabrics, they must create a form-fitting bodice and floaty skirt that embodies the glamour that makes the maxi dress popular to this day. Who will boogie their way to garment of the week, and for whom will 70s week signal the end of an era, as they become the third sewer to wave goodbye to the Great British Sewing Bee?