Leaders of Britain鈥檚 biggest cities outside London have urged Labour to get behind the North-South high speed rail line - as the Government prepares for a Parliamentary battle which could extend up to the next election.

Sir Albert Bore, leader of Birmingham City Council, met David Cameron in Downing Street to back the rail line known as HS2, alongside council leaders and mayors from Bristol, Leeds, Liverpool, Manchester, Newcastle, Nottingham and Sheffield as well as Glasgow and Edinburgh.

They handed over a letter urging Labour to unite with the Government to back the rail line when legislation allowing the first phase to be built is presented to Parliament next week.

The High Speed Rail Bill, an unusual type of legislation known as a hybrid bill, will lead to a series of evidence sessions in the Commons beginning next year, in which people affected by the new line will be allowed to argue for changes to the route or higher compensation.

At the same time, Mr Cameron faces pressure from some Conservative backbenchers who oppose the line, while Labour鈥檚 official position is unclear.

The line, which could cost 拢28.2 billion with 拢14.4 billion of contingency funding, was originally a Labour project launched by the last Government. But Shadow Chancellor Ed Balls has said a future Labour government could scrap the scheme and spend the money on housing instead.

Council leaders also urged the Prime Minister to ensure the planned high speed rail line extends to all of Britain鈥檚 major cities and on to Scotland.

The North-South line will run from London to Birmingham in the first phase, before a second phase extending it to Manchester and Leeds is built. Trains will continue to Darlington and Newcastle, but only running at standard speeds north of York.

City leaders want the Government to look at extending the line to Newcastle, and on to Edinburgh and Glasgow.

The letter said: 鈥淭he purpose of this document is to express unwavering support for High Speed 2, to call on the Coalition Government and Her Majesty鈥檚 Loyal Opposition to unite and press on with the Hybrid Bill for phase 1 of the project, and to urge the Government to deliver with all speed final plans for phase 2. But our ambition should not stop there and we also want to explore with Government the costs and benefits of expanding a network that extends High Speed 2 to all of the great cities of our country.鈥

Sir Albert said: 鈥淗igh Speed 2 is an essential step toward a 21st the whole of the 海角视频. We see no credible alternative to achieving our wider economic vision.

鈥淭he 海角视频 lags behind the competition in its infrastructure. The existing rail network no longer has the capacity to support the increased levels of demand for rail travel that there will be within the next decade.

鈥淯pgrades will not do, and will instead cause years of delays and economic damage not just for cities, but for the 海角视频 as a whole. Understanding the benefits this will bring is of course essential, but we believe the case has been made for this investment, which is roughly the same annual sum as that spent on Crossrail in London, and will connect all the 海角视频鈥檚 cities as a single economic powerhouse鈥.

Mr Cameron attacked Labour for failing to make it clear whether it supports the line. He said: 鈥淚 was really pleased to welcome Sir Albert Bore 鈥 leader of Birmingham City Council - to Downing Street to talk about HS2. Although he鈥檚 from a different party to me, we鈥檙e both in agreement on this: a high speed North-South railway is vital for the future of Birmingham.

"This shouldn鈥檛 be about politics 鈥 it鈥檚 something we can all support. This new railway will bring huge benefits to Birmingham: it鈥檒l attract new businesses, create jobs and add as much as 拢3 billion to the economy here. It鈥檒l link our cities up better, cut journey times and ease congestion. Put simply, if it鈥檚 easier and quicker to get here, firms are more likely to set up shop.

"The only people who don鈥檛 get this are Ed Miliband and Ed Balls. They seem to care less about the future of Birmingham than playing political games. One day they say they鈥檙e right behind this new railway, the next they say they鈥檙e thinking about spending the money on something else. They need to be clear about whether or not they support HS2.

"In recent months we鈥檝e seen lots of encouraging signs that the economy is turning a corner. There are 25,000 more people are in work in the West Midlands compared to 2010 鈥 and 25,000 new businesses too. What鈥檚 important now is that we push on and finish the job we started. A new North-South line is a critical part of that plan, a long term decision we鈥檝e got to take. It鈥檚 time to stop the political bickering and get this railway built."