The exclamation leg it! will today most likely be heard from a younger member of the working class English to instruct his peers to flee a would be assailant, an authority figure, or any other situation that warrants escape or rapid retreat.
The phrase originated in the 17th century when the most common form of freight transport was by barge. Although horses were used to pull the barge and its payload along open sections of canal they were unable to do so through tunnels. In order to navigate a tunnel, men known as leggers were employed to push the barges through. By lying face up on the barge and pushing against the tunnel walls and roof, the legger would walk a barge through the tunnel. It could take up to 2 hours to leg a barge through the longer canal tunnels such as 'Mile Tunnel' at Foulridge on the Leeds Liverpool canal.
Legging was stopped in the 1800's when it was reported that a legger died of asphyxia.
