Roaring into the 1940s Chris finds out there's nothing like a war to create technological change. He mans a fire pump to tackle a Blitz-style blaze and steps into an RAF control centre to discover how radar helped win the Battle of Britain. From spy planes to powerboats, jet engines to shrapnel-proof fire engines, Chris shows how new innovations helped defeat Hitler. But then we needed brand new tractor and car designs to help build the peace that followed...

• Chris Barrie