The Lower Lea Valley Cable Tunnels, known as the PLUG (Power Line Under Ground) Project during construction, are a pair of 6 km cable tunnels running beneath the lower Lea Valley in east London.
Constructed at a cost of £130m ahead of the 2012 London Olympic Games, they are owned by National Grid plc and UK Power Networks.
[2] One tunnel is 4.15m in diameter and carries a 400 kV circuit as part of the National Grid, while the other tunnel is 2.82m in diameter and carries a 132 kV circuit as part of the London power distribution network.
The tunnels replaced two over ground power lines which crossed the area which would be turned into the Queen Elizabeth Olympic Park.
[4] More than 200,000 cubic metres of spoil was generated, the majority of which was reused in the construction of the Olympic Park.