Conservatives have warned they may reject the findings of a Government review into the route of a new high speed rail service between London and Birmingham.

Tory Shadow Transport Secretary Theresa Villiers has turned down an offer from Transport Secretary Lord Adonis of an advance look at the proposals, which are published in March, drawn up by a panel appointed by the Government.

She said details of the exact route should be decided through public consultation, and not by “a cosy political consensus” behind closed doors.

Tories have always said they will not be bound by the findings of the Government inquiry. Speaking to the Birmingham Post last August, Ms Villiers said Conservatives were working on their own plans in partnership with industry experts such as engineering firm Arup, because their vision for a high speed rail line was different to Labour’s.

Conservatives have pledged to build a national network including Manchester and Leeds as well as London and Birmingham. Labour is promising a service between the capital and the West Midlands, with the option of expanding it in future decades.

Tories also want to include links to Heathrow because they see high speed rail as an alternative to building a third runway at he airport, while Labour supports the runway.

But Lord Adonis has argued that the multibillion-pound 200mph link must be “above politics” if it is to succeed.

And a newspaper has claimed the Tories are wary of angering communities in dozens of constituencies along the route which could be named in the Government report, particularly in the wealthy Chilterns area.

The proposals are understood to lay down a precise route for the track to within five metres of accuracy in urban areas and 25 in the countryside, cutting through Conservative heartlands in Buckinghamshire and fiercely-contested swing seats in the West Midlands.

Shadow transport secretary Theresa Villiers said she did not want to “close down the options” on the link ahead of the consultation process which will follow publication of the plans.

She said: “We appreciate the offer to see the report, but we don’t want the report to close down the options.

“This is one of the most important decisions we will be making on our transport infrastructure for the next 20 years.

“I very much hope there is going to be valuable work in the White Paper when it is published. It will be an important contribution to the debate, but we can’t let it close down the options.

“We will look at it when the whole of the general public gets a chance to look at it. We don’t want there to be some cosy deal reached behind closed doors which closes out the communities which might be affected by the route.”

Liberal Democrat transport spokesman Norman Baker said: “This stance taken by the Tories clearly suggests that they’re rowing back from their commitment on high-speed rail (HSR).

“Seeing the document doesn’t commit any party to a particular line, but it is a useful way of learning what’s on the table and informs the debate.

“This peculiar decision of the Tories coupled with (shadow chancellor George) Osborne’s spending cuts strongly suggest that the Tories are trying to kick HSR into the long grass. The Tories can’t be trusted with our railways.”

And Professor Stephen Glaister, director of the RAC Foundation, added: “It seems bizarre that the Conservatives have turned down the opportunity to scrutinise the HS2 report.

"All parties are advocating high speed rail yet now Theresa Villiers is refusing the opportunity to see the official, independent, study into a new line, and the public might conclude that she is happy to base her party’s views more on faith than fact.

"One is left wondering whether she now believes the HS2 report won’t be as supportive of a new north-south line as everyone is being led to believe.“

“We are not suggesting new road schemes would be any less controversial in terms of planning, but the public have a right to know the truth about any new infrastructure proposals. In the interests of transparency Lord Adonis needs to make the HS2 report public now.” 

Plans for a new high-speed rail link cutting the London to Birmingham journey to just 45minutes were unveiled by Conservatives when they held their annual conference in the city in 2008. Labour announced it would also build a high speed rail line in January 2009.