The National Grid is overseeing a £1billion project to rewire South London with a network of underground tunnels.

Launched in Spring 2020, the project will help improve electricity supply.

The National Grid’s new tunnel network in London (Image: National Grid)

It will involve the construction of 32.5km of tunnels with a diameter of three metres.

The tunnels are being built below the road network connecting Wimbledon and Crayford.

Usually, maintenance work on the high-voltage cables is carried out overground, but this can be a lengthy and disruptive process.

Part of the network was switched on earlier this month (Image: National Grid)

Underground tunnels will help make the work less disruptive to traffic, locals, and businesses.

More cables can also be added to expand the network’s capacity.

The project is expected to be completed by 2027 after the first phase was completed in 2018.

In August, the new electricity transmission circuits were switched on for one-and-a-half miles of the network.

Alice Delahunty, president of National Grid Electricity Transmission, said: “There’s still a way to go on the project, but the Hurst-Crayford circuit seeing volts for the first time is a tremendous achievement for our National Grid teams and supply chain partners.

“It’s hard to overstate what an engineering challenge it has been to build over 20 miles of tunnels under London to upgrade and futureproof the capital’s electricity supplies, so the project’s progress to date is a real testament to all those involved.”

Energy minister Michael Shanks added: “The London Power Tunnels show British infrastructure at its best and I congratulate the efforts of everyone involved, as this new circuit switches on to power up homes and businesses across the capital.”