A preferred route for the proposed Crossrail 2 scheme connecting north and south London has been published by Mayor Boris Johnson and Transport for London.
The £20bn rail link would run from Cheshunt in Hertfordshire to Epsom in Surrey, passing through Clapham Junction, Victoria and Tottenham Court Road.
As well as helping to alleviate overcrowding on existing rail and Tube services, City Hall says the project would support the construction of 200,000 new homes.
TfL will now ask the Government, which must approve the scheme, to protect the proposed route from further development following a Department for Transport consultation with landowners and local councils.
If ministers give the go-ahead, the first trains could be running by 2030.
Publishing the route, Mayor Johnson said: “With London’s population soon to surpass its previous 1939 peak of 8.6m, and with more people travelling by Tube and rail than ever before, we need additional rail capacity to support future growth.
“For the capital to remain globally competitive there needs to be continued investment in our transport network and that’s why we have to get cracking on planning for Crossrail 2.
“It’s an essential infrastructure project that will deliver thousands of new homes and jobs, as well as helping to keep our great city moving.”
The Mayor’s office says work is now underway to identify funding options and added that Mr Johnson believed the scheme’s “wider UK economic and transport benefits” meant the government should make a contribution to its costs.
Labour’s London Assembly transport spokesperson, Val Shawcross AM, said Crossrail 2 would have “a transformative effect on the capital and the surrounding regions, opening up vast new areas for regeneration and creating new jobs and economic opportunities.”
She added: “Whilst the announcement of a preferred route is significant, what we need to see now is the fully worked-up funding package which will make this project a reality.”