List of tunnels in the United Kingdom
This is a list of road, railway, waterway, and other tunnels in the United Kingdom. A tunnel is an underground passageway with no defined minimum length, though it may be considered to be at least twice as long as wide. Some government bodies define a tunnel as in length or longer. A tunnel may be for pedestrians or cyclists, for general road traffic, for motor vehicles only, for rail traffic, or for a canal. Some are aqueducts, constructed purely for carrying water—for consumption, for hydroelectric purposes or as sewers—while others carry  other services such as telecommunications cables. There are even tunnels designed as wildlife crossings for European badgers and other endangered species. The longest tunnel in the United Kingdom is the Northern line at . This will be superseded in 2021 by the Woodsmith Mine Tunnel in North Yorkshire that will transport polyhalite from North Yorkshire to a port on Teesside. Standedge Tunnel at is the longest canal tunnel in the United Kingdom.