David Cameron has accused Labour of “an immense slap in the face to the West Midlands” after Shadow Chancellor Ed Balls cast doubt on plans to complete the planned high speed rail line.

Mr Balls said he wanted to build a new line running east to west across the country before completing “phase two” of the planned £50 billion rail line, which would run from Birmingham to Manchester and to Leeds.

The first phase of the line, from London to Birmingham and due to begin construction in 2017, would go ahead as planned, although Labour will want reassurances that it is begin built in the most cost-effective way possible.

But Mr Cameron said it was essential the second phase of the line was built too.

He said: “I would say to anyone who says there isn’t a case for HS2, try getting on the train from Birmingham to London or London to Birmingham and see how many people are standing, see how much extra capacity we need.

“So the case is very strong and has been proven over and over again.

“But the very worrying news today is that Labour are calling into question apparently the links between Birmingham and Manchester and Birmingham and Leeds, and this would be an immense slap in the face from Labour to the West Midlands, the East Midlands and the North of the country and I cannot believe they are contemplating letting down British people in vital regions of our country in this way.”

And his comments were echoed by London mayor Boris Johnson, who was in the West Midlands to support Conservative candidates in the forthcoming general election.

Mr Johnson said: “I think it is totally deranged. I think it is Labour turning its back on the West Midlands, the Midlands, the East Midlands and the north of the country. Why would you do that?”

Mr Balls told the Birmingham Post that he would ask Sir David Higgins, the Executive Chairman of HS2 Ltd, to examine whether the proposed second phase of the line offered the “best connectivity and best jobs and investment opportunities for Liverpool and Hull and Newcastle as well.”

And in the meantime, he would bring forward proposals which are currently at the very earliest stages for a so-called HS3, which would run from the east to the west of the country.

Ed Balls
Ed Balls: New east-west line "should be done before the second phase of HS2"

Speaking at Westminster, the Shadow Chancellor said: “I will want to be discussing how we can improve east-west links. I think that is something we get on with quickly while we ask big questions about the second phase of HS2.”

He added: “I will want to be discussing how we can improve east-west links with David Higgins from day one and I think that is something we get on with quickly while we ask big questions about the second phase of HS2.”

Mr Balls said: “The idea that we wait to do east-west until after we have done the second phase of north-south is topsy turvy.

“It has no economic or business logic at all.”

And criticising the current proposal to begin work on HS3 only after the entire HS2 line was completed after 2033, he said: “I don’t understand this proposal for HS3. Why would you decide to spend 20 years improving north-south links before, finally, in the third phase, coming to east-west?

“I think George Osborne has got this wrong.

“And our view is that it shouldn’t be HS3 - it should be done before the second phase of HS2.

“I think getting on and doing east-west now is the priority.”

While an east-west line would probably run across the Pennines, connecting North West cities such as Manchester and Liverpool to cities in Yorkshire and the North East, such as Leeds and Newcastle, Mr Balls also suggested Birmingham, in the West Midlands, could have a new connection to Nottingham, in the East Midlands.

Last year business leaders and councils in the East Midlands and West Midlands, which have formed a body called Midlands Connect, publishes a report highlighting the economic benefits which would come from improvng rail links between the two regions.

Earlier this week the House of Lords Economic Affairs Committee urged MPs to block legislation allowing construction of HS2 until the Government can prove it has seriously considered other options – including improving connections between cities in the north of England first.

The battle for power

Our interactive poll-of-polls draws on every opinion poll published by each of the main polling companies over the last 100 days:

"Poll Tracker"
We're testing a new site: This chart is coming soon