The inside story of Guy's attempt to break the motorcycle land speed record: his fastest and most dangerous speed challenge to date. Can he become the first man to do 400mph on a motorcycle? To watch the full episode click here - https://www.channel4.com/programmes/speed-with-guy-martin/on-demand/61928-001 #GuyMartin #LandSpeedRecord Welcome to the only official Guy Martin Proper YouTube channel. Make yourself a cup of tea or twenty & follow every race, every build and every country Guy visits. Fair play. Subscribe here https://bit.ly/2OwyYOY