London's Crossrail project is running £600 million over budget, it has been announced.
The scheme's budget has been increased from £14.8 billion to £15.4 billion, Rail Minister Jo Johnson revealed in a written statement published on the final day of the parliamentary term.
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He said "cost pressures have increased across the project" but the Department for Transport (DfT) and Transport for London (TfL) "remain committed to the successful delivery" of the new east-west railway.
Transport Secretary Chris Grayling sparked anger in July last year by supporting a new £30 billion Crossrail 2 scheme in London and the South East days after a series of rail electrification projects in Wales, the Midlands and the North were axed or downgraded.
The DfT and TfL are each providing £150 million of additional funding to Crossrail Limited, while an extra £290 million for the completion of work on the national rail network is being paid for by the DfT and Government-owned Network Rail.
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Mr Johnson wrote: "It remains the case that over 60% of the project's funding has been provided by Londoners and London businesses."
He stated that Crossrail is 93% complete and is entering "the critical testing and commissioning stage".
The railway is known as Crossrail during the construction phase but will become the Elizabeth Line once services begin.
Trains will operate on three routes from December: Paddington to Abbey Wood, Paddington to Heathrow and Liverpool Street to Shenfield.
The line will fully open in December 2019, with trains running from Reading and Heathrow in the west through 13 miles (21km) of new tunnels to Shenfield and Abbey Wood in the east.