Police are investigating a video clip posted on YouTube which appears to show a motorcyclist driving at 125mph on a motorway. The three-minute film shows other motorists swerving to avoid the car in the outside lane of the M23 in Sussex.
"If identified, strong consideration will be given to prosecution. It was a stupid thing to do," said a spokesman for Sussex Police.
According to YouTube, a successful flagging system lets users alert the website of inappropriate content.