Guy Martin hints he's ready to break 300mph land speed record You can do it Guy! Guy Martin has hinted he's ready to try the 300mph land speed record challenge again (Image: Guy Martin/Facebook) Petrolhead Guy Martin looks set to attempt a new land speed record this year, aiming to be the first person to achieve a speed of 300mph on a motorbike. In a social media post, the motorcycle racer turned TV personality has hinted he will be embarking on the challenge soon as he is pictured stood next to his latest speed machine. He goes on to list a number of contributors who have helped get the motorcycle ready as well as revealing he has been practicing at airfields across the UK.