Fair Isle garments made with pure Shetland wool were - and still are - often knitted by skilled but poorly paid out-workers. With the advent of man-made fibres such as acrylic which made the production of high-fashion, machine-knitted sleeveless tops very cost-effective, authentic knits became - and remain - expensive. Photographer Chris Morphet visited Shetland in 1970 when it was on the cusp of change; his marvellous work illustrates a huge variety of Fair Isle knitting.