Work is underway to build a new 12.5km cable tunnel underneath Greenwich and Lewisham, a £17 million scheme to upgrade the electricity network for south east London.

UK Power Networks, a major electricity distribution firm, say the new cable route is set to replace old cables which were first installed in 1958.

The project will help ensure the reliability of local power supplies from Sydenham to Eltham, ensuring it is "fit and flexible for the future."

The company say more than 300,000 people in south east London will benefit from the £17 million investment when it is completed in autumn, the project "representing a growth in network capacity to meet increasing demand."

Jason Taylor, senior project manager, said: “This cable upgrade is part of our ongoing investment in the network to maintain reliable power supplies.

"The new cable route has already been built and the aim is to test the cable connections as we go along, to ensure a smooth transition for when the project is completed early next year.”

The cables have been installed a metre underground, passing under a river and the route includes three railway under track crossings.

As part of the scheme, the company consulted local councils and parties to ensure "that people experience as little disruption as possible while excavation work takes place."

Liam O’Sullivan, head of programme management and delivery at UK Power Networks, said: “We are making sure the electricity network is fit and flexible for the future. This work will represent further growth in our network capacity to meet the increasing demand.”