The idea of deliberately trapping air within a garment is really interesting—it’s the same reason that a string vest can keep you warm, or cool.
And while Rab C Nesbitt is not perhaps the most obvious source of design inspiration, his favoured style of undergarment is a tried and tested ‘technical’ garment for use in extremely hot and cold climates. In 1953 the expedition team climbing Everest wore string vests, layered underneath a shirt and a Shetland jumper. Like Rab C, my father was a year-round string vest man: it is a piece of clothing that is firmly planted in my psyche!
Traditional, light weight Shetland lace knitting uses an unbelievably fine yarn. Again, with the air pockets created by the lace pattern, these garments can be surprisingly warm.
Of course animal fur also traps air, which keeps the creature warmer than a super-sleek coat. You might be interested to know that one of the other sources of inspiration for the Rigg fabric came from the natural world— but definitely not Shetland—being the pattern of a crocodile hide! I’m afraid the design process is seldom neat and tidy, and my influences and ideas come from a wide variety of sources.