The project that became Crossrail has origins in the 1943 County of London Plan and 1944 Greater London Plan by Patrick Abercrombie.
Positioning a new station at Paddington presented structural design challenges due to its positioning just below Eastbourne Terrace and the station's taxi rank, and within 3 metres of Isambard Kingdom Brunel's 150 year old mainline station.
Crossrail is a 118-kilometre (73-mile) railway line under development in England, running through parts of London and the home counties of Berkshire, Buckinghamshire and Essex.
The central section and a large portion of the line, between Paddington in central London and Abbey Wood in the south-east, are due to open in December 2018, when it will be named the Elizabeth line in honour of Queen Elizabeth II.
The cost of the east–west scheme including rolling stock was estimated at £885 million. A more ambitious proposal named "Superlink" was proposed in 2004, at an estimated cost of £13 billion, including additional infrastructure work outside London: in addition to Crossrail's east– west tunnel, lines would connect towns including Cambridge, Ipswich, Southend-on-Sea, Pitsea, Reading, Basingstoke and Northampton.
Both the Labour and Conservative parties made commitments in their manifestos for the 2010 election to deliver the railway, and the coalition government formed after the election also committed to the project.
Although the idea was seen as imaginative, only a brief estimate of cost was given: £300 million.