The UK National Infrastructure Commission (NIC) has recommended the proposed Crossrail 2 project should move forward to construction as quickly as possible.
The commission urged the government to strengthen support for development of the Crossrail 2 link across London, describing the northeast-southwest line as a ‘priority’ for the city.
In a report entitled Transport for a World City, the NIC identifies four challenges that will face London’s rail network from the late 2020s.
These include overcrowding on key Underground lines, lack of capacity on commuter lines and at major main line stations, insufficient orbital links, particularly in the east of the city, and the need for transport to promote housing growth.
In the report, it was also noted that congestion is forecast to be particularly acute on north-south Underground lines, commuter services in the southwest of the city, and at major stations on these routes.
The commission noted that funding should be made available at once to develop the project, with the aim of submitting a hybrid bill by the second half of 2019 and getting it built by 2033.
Initially, sufficient development funds should be released for Transport for London (TfL) and the Department for Transport (DfT) to prepare a hybrid bill for Crossrail 2, beginning with a revised business case to be submitted by March 2017.
In developing the business case, it is crucial that both TfL and DfT identify clear proposals to maximise its benefits and increase deliverability.
NIC chairman Lord Andrew Adonis said: "By the 2030s, London will be a megacity of more than ten million people.
"Even allowing for planned investment and the imminent arrival of the east-west Crossrail line, the capital will grind to a halt unless significant further improvements are made.
"That’s why London needs Crossrail 2 as quickly as possible.
"A new northeast to southwest line would help relieve severe overcrowding across some of the busiest Network Rail stations in the country, and the most congested Underground lines and overground commuter routes.
"The Commission has identified four crucial ways in which the scheme can be developed to ensure that we maximise benefits and increase deliverability: phasing parts of the scheme, fair funding with London paying more than half the cost, private financing to help build stations and, crucially, a clear, transformative strategy to turn the proposed 200,000 new homes into a reality."
In October, the NIC was asked to review the strategic case for additional large scale transport infrastructure in the capital and its region, with particular reference to proposals for a new northeast to southwest Crossrail 2 line.
The proposed Crossrail 2 is designed to provide a new central London artery connecting the suburban railway network in the southwest to lines in the northeast via a brand new tunnel from Wimbledon to Tottenham Hale.
The new line will relieve or strengthen major suburban and Underground lines, as well as a string of Network Rail’s busiest stations, while opening up new areas for housing and regeneration.