London Fire Brigade said they were dealing with a blaze causing power outages to around 38,000 customers. The cause of the fire was unknown, they said.

Services on the Docklands Light Railway line, which links Canary Wharf to the city of London, were affected and the area’s two major river crossings, the Blackwall and Rotherhithe road tunnels, were closed.

UK Power Networks, which owns and maintains electricity cables and lines across London, said there had been a network fault. They did not confirm how this was related to the substation fire.

Their website showed power cuts right across the capital, citing the cause: “A fault occurred on a high voltage underground electricity cable in the local area.”

A few shops in the mall beneath the Canary Wharf skyscrapers were forced to close or operate with their lights out, while some office buildings relied on backup generators to keep running.