This is one of the most ambitious homes ever seen on Grand Designs – a scaly, curving house reminiscent of a giant coiled snake in a field. Stephen Tetlow is head of the Institution of Mechanical Engineers, wife Elizabeth is a committed horticulturalist. Together they want to build a home that reflects both their passions – one that pushes Stephen’s engineering skills to the limit and embraces Elizabeth’s deep affinity with nature. Taking inspiration from an ammonite shell found on their land in the beautiful Blackdown Hills in Devon, the house spirals onto the landscape over two levels and mixes natural materials with cutting edge technology.

Construction of such a complex curving structure proves a huge challenge and progress is tortuously slow. It doesn’t help that engineering mastermind Stephen is working in London every week, so the pressure is on Elizabeth to project manage on site. They struggle to keep within their original 12 month schedule to move in and when their £600k budget runs short, have to clad the roof in 4600 wooden slats themselves. It’s a huge, gruelling labour of love – but if they pull it off it could be magnificent…