The government says an illegal immigrant sneaked into the U.K. by smuggling himself aboard a bus full of British border agents.

Britain's Home Office says the man hid in the small space between the bus's chassis and its fuel tank as it traveled through the Channel Tunnel from the French town of Coquelles to the British coastal city of Dover.

The Daily Mail newspaper reported Saturday that the bus carried at least 20 Border Agency staff, whose job it is to keep illegal immigrants out. The newspaper says the man was spotted dropping from the bus on to the road but ran away before he could be caught.

The Home Office said the incident occurred within the last week but could not immediately give a precise date. It said the man has not been caught.