A plan to link south west and north east London through a second Crossrail tunnel was unveiled this morning by business group London First, with former transport secretary (and potential mayoral candidate) seated squarely in the driver's cab.
Crossrail 2 isn't a new concept: a "Chelney" line, between Chelsea and Hackney, has been under discussion since the
1970s 1930s (thanks to commenter Chris5156 for that correction), and the route has been safeguarded since 1989. The proposal released this morning calls for a route linking parts of Surrey, including Chessington and Shepperton, with hubs in north east London including Seven Sisters and Dalston Junction, via central London stations including Victoria, King's Cross and Angel.
In central zones the route would mimic the Victoria line's path, alleviating what is one of London's less commodious Tube lines (it currently runs the "most intensive" service in the country, according to Transport for London). Commuters shouldn't get their hopes up yet, though: construction on Crossrail 2 isn't being considered until the early 2020s, with the service opening in 2030. And there's the issue of the estimated £12 billion price tag.
Still, as the BBC's Tom Edwards notes, the support from business is significant, and could mean that they are willing to pay some of the costs; a situation we've also seen in the Northern Line extension, which is being part-funded by the redevelopment of Battersea Power Station. Whether the political will to hand over another few billion pounds to TfL exists is another matter.