Boris Johnson has given HS2 the go-ahead, despite fears over its cost and impact on the environment.

The Prime Minister told the House of Commons that his Government had the “guts to take the decision” to deliver prosperity across the country.

READ MORE: HS2 ‘could exceed budget by £30 billion’

To avoid “further blow outs” in HS2’s cost or schedule, a series of measures will be taken to “restore discipline to the programme”, he said.

This will include appointing a minister whose full time job will be to oversee the project, and changes to the way HS2 is managed.

Mr Johnson added: “This is not just about getting from London to Birmingham and back.

“This is about finally making a rapid connection from the West Midlands to the Northern Powerhouse, to Liverpool, to Manchester, to Leeds and simultaneously permitting us to go forward with Northern Powerhouse Rail across the Pennines – finally giving the home of the railways the fast connections they need.

“And none of that, none of it makes any sense without HS2.”

He added: “The Infrastructure and Projects Authority considers that this first phase can be delivered for its current projected costs of £35 billion to £45 billion in today’s prices.”

Mr Johnson said: “If we start now, services could be running by the end of the decade.

READ MORE: Boris Johnson says eagerly-awaited decision on HS2 will arrive 'very shortly'

“So today the Cabinet has given High Speed Rail the green signal. We are going to get this done.

“And to ensure that we do so without further blowouts on either costs or schedule we are today taking decisive action to restore discipline to the programme.”