The hawk-eyed Gary Cook spotted a £189 bamboo helmet, made by Roof. Aesthetics aside, bamboo might not seem an obvious choice. Yet as well as being the planet's fastest growing plant (he typed, sending a quick little prayer of thanks to Google), bamboo's tensile strength is 28,000 per square inch, vs 23,000 for steel. Each strand of the grain is perfectly straight, and without branches or knots (save the occasional, but regular, knuckle), it has no weak points. The wood has been used to make suspension bridges, houses, even bicycles. Now you can wear it to stop your noggin getting squished like ze melon when you fall off your eco-scooter.