Roger Shawyer has developed an engine with no moving parts that he believes can replace rockets and make trains, planes and automobiles obsolete. “The end of wings and wheels” is how he puts it. It’s a bold claim. Of course, any crackpot can rough out plans for a warp drive. What they never show you is evidence that it works. Shawyer is different. He has built a working prototype to test his ideas, and as a respected spacecraft engineer he has persuaded the British government to fund his work. Now organisations from other parts of the world, including the US air force and the Chinese government, are beating a path to his tiny company. The device that has sparked their interest is an engine that generates thrust purely from electromagnetic radiation – microwaves to be precise – by exploiting the strange properties of relativity. It has no moving parts, and releases no exhaust or noxious emissions. Potentially, it could pack the punch of a rocket in a box the size of a suitcase. It could one day replace the engines on almost any spacecraft. More advanced versions might allow cars to lift from the ground and hover. It could even lead to aircraft that will not need wings at all. I can’t help thinking that it sounds too good to be true.