TODAY’S TV Couple shells out to build their dream home K

EVIN McCloud is channeling Sir David Attenborough tonight. Crouching in a bush, he’s holding a coiledup fern leaf.

“Build with this shape and build at your peril,” he warns. “Build with this shape and you enter the terrifying world of... the spiral!” Cue dramatic cut to opening credits.

Nature has indeed provided the inspiration for tonight’s build – billed as one of the most ambitious homes ever seen on Grand Designs.

Now we know they’re always saying that, but honestly, once you see the giant curved house that looks like a coiled snake, you’ll be impressed, pretentious though it all might be.

The daring couple with the grand idea are Stephen Tetlow, head of the Institution of Mechanical Engineers, and his wife Elizabeth, a horticulturalist. With him a practical scientist and she a lover of nature, they wanted to build a home that brought both their passions together.

“We were talking to an architect and on our kitchen table was an ammonite fossil, and it evolved from that,” explains Stephen.

The ammonite shell, found on their land in the Blackdown Hills in Devon, inspired them to build a house that spiralled onto the landscape over two levels, mixing natural materials with cutting edge technology.

Kevin first met them in 2015, back when this was all just a plan, a dream and a chunk of bare land. Some nifty graphics give us a rough idea of what’s in store – the house will swirl around an ornamental garden.

Two words spring to mind at this point – complicated and expensive. But the couple only have a budget of £600,000 and want to move in in 12 months.

“But nothing is straight, everything is round!” says the contractor as the real graft begins. Progress is slow, but as ever, you’ll be desperate to see the big finish.