The budget for the first phase, between London and Birmingham, has been set at £21.4bn. This phase is planned for completion by 2026.
The budget for the second phase, taking the lie further north to Leeds and Manchester by 2032, has been set at £21.2bn.
The figures include £14.4bn of contingency funds across the scheme.
Transport secretary Patrick McLoughlin told the House of Commons yesterday that the £42.bn figure was a ceiling rather than an estimate. "While I expect the final costs to be lower than those I have just outlined,” he said, “this is the right way to plan the project."
MPs yesterday voted overwhelming to give the project’s enabling Bill a second reading.