A senior Government minister has threatened to resign over HS2 unless his constituency is guaranteed sufficient help dealing with the impact.
David Lidington said he would not join dozens of rebel Tory MPs expected to vote against the proposed high-speed rail link in the Commons this evening.
But the Europe Minister, who is missing tonight's vote on an official trip to Estonia, vowed to sacrifice his job in future if he failed to secure adequate mitigation and compensation for the Aylesbury area.
Efforts to block the £50 billion link between London and the North of England are being spearheaded by ex-Conservative vice-chairman Michael Fabricant and former cabinet minister Cheryl Gillan and are tipped to attract the support of up to 40 MPs.
The principle of the HS2 project is set to clear its first Commons hurdle easily however after Labour signalled that it was maintaining its support, despite previous concerns over the cost and benefits.
Mr Fabricant, the Lichfield MP who blames his opposition to the line in part for his removal as vice-chairman, claims that between 80 to 100 of his fellow MPs have "really serious doubts" about the line - which is routed through several strongly-Conservative rural areas.
But many were reluctant to "use up our stocks" with the party's enforcers when the project is expected to clear its second reading thanks to support from Labour.
Mr Lidington is one of several ministers in affected seats who are expected to miss the vote on official business - thus avoiding a whip-defying vote against the Government line that would almost certainly mean leaving the front bench.
"I have decided to abstain, but I have been and remain opposed to HS2, I've fought alongside campaigns and the Prime Minister knows my views," he told the Bucks Herald newspaper.
"The key test for me is: given there is a massive cross-party majority in favour of this scheme, can we get the generous and fair mitigation that the local area deserves?
"I will resign at a later stage of the bill if they don't get mitigation, and that for me includes a Chilterns tunnel."
He said he understood local criticism of his decision not to register his protest in the Second Reading vote.
"I thought long and hard about what I should do.
"But given the harsh reality of parliamentary arithmetic I felt that the best outcome would be to stay and fight for the mitigation and compensation that people deserve.
"If I stood down I would just be one more MP that is against HS2, but by staying in I have the inside track, it's a pragmatic political judgment."
Stepping down would be destabilising while he was dealing with issues such as the Ukraine crisis, he suggested, which he is to discuss with his Estonian counterpart before speaking at an internet freedom conference.
He was booked for the event before the HS2 vote was scheduled, he told the local newspaper.
Mrs Gillan's objection, which has the support of Labour former ministers Frank Dobson and Kate Hoey, argues that attempts to justify the benefits of HS2 had been "repeatedly unconvincing and still fail to demonstrate a sound economic case for the proposed works".
The MPs say there has been "inadequate opportunity" for those affected by the High Speed Rail Bill to examine all the evidence and condemned Transport Secretary Patrick McLoughlin for refusing to release the Major Projects Authority (MPA) report.
Prime Minister David Cameron said he expected a big Commons majority in favour of the Bill.
"Let's be clear on why we are doing it - the West Coast Main Line is full, the capacity has run out," he said during a visit to a JobCentrePlus in Colchester, Essex.
"So we have a choice as a country: do we build another standard railway line or do we build a high-speed railway line that can massively add to the capacity of our country, help end the North-South divide, and help make sure all our country shares in future prosperity.
"I think it is right for Britain to get on board the high-speed rail revolution and I expect the House of Commons to endorse it in a big vote tonight."
The Institute of Economic Affairs published research which claims there are "numerous reasons to be sceptical" of the Government's assertions that the new line would boost employment and address the North-South divide.
The think-tank cited east Kent as an area where the impact of high-speed rail appeared to have been "too small to counteract other more important economic factors".
Construction of the first stage of the HS2 project, linking London to Birmingham, is proposed to begin in 2017, with the second phase of the scheme then going north to Manchester and Leeds.
The full HS2 link between London, the Midlands and the North of England is expected to cost £42.6 billion, which includes contingencies, with £7.5 billion for the trains.
Attorney General Dominic Grieve - like Mr Lidington, a Buckinghamshire MP, representing Beaconsfield - will also skip the vote as he has ministerial engagements in Newcastle, which his office said were long planned
Andrea Leadsom, a vocal critic of the scheme before being made a Treasury minister in the last reshuffle, is in Brussels.
The Prime Minister's official spokesman said of the Europe Minister: " My understanding is that his trip to Estonia has been planned for some time."
A ComRes poll of 150 MPs suggested a third favoured the scrapping of HS2 in favour of a new plan - with 53% in favour of going ahead.
The proportion of opponents was broadly the same across all three main parties.
As many as 44% backed diverting some of the funds earmarked for the project to expanding existing capacity, with 39% opposed.
ComRes spoke to 55 Conservative, 77 Labour, 10 Liberal Democrat and eight others between March 3 to 24.
Andrew Hawkins, ComRes chairman, said: "Despite the whipped vote tonight, our poll reveals the true extent of unease among MPs of all parties towards HS2.
"Given the level of opposition among his own backbenchers, this threatens to be another blow to the Prime Minister's standing within Parliament."
Labour MP Mike Kane said: "First Andrea Leadsom, now David Lidington - ministers are openly thumbing their noses at David Cameron over HS2.
"Any Prime Minister worth his salt would act against such open rebellion but he seems powerless to do anything about it. If he can't even get his own people to support him, what exactly is the point of this out of touch Prime Minister?"