Balfour will start delivering all aspects of track renewal work from April – including track, points and crossings, and trackside drainage.

The contract will start in April 2019 and last for four years, with an option included to extend the contract for up to a further six years.

It replaces a previous eight-year agreement with Balfour, which contributed to modernising around 75 % of the Tube network.

David Wylie, Transport for London’s chief procurement officer, said: “This contract is designed to promote a strong working relationship between London Underground and Balfour Beatty.

“The contract has incentives built in that create a strong focus on safe and reliable delivery allowing TfL to maintain the best possible safety standards and ensuring a reliable service for its customers. The agreement also encourages consistent improvement and innovation while controlling costs.”

Mark Bullock, Balfour Beatty’s Chief Executive Officer for its Rail and Utilities business, said: “This award is testament to our continued focus on driving innovative solutions that deliver sustainable, safer rail infrastructure at reduced cost.”