An overwhelming majority of MPs have voted in favour of the HS2 paving bill following a debate in the Commons.
The vote came after the Government announced the budget for the controversial line has jumped by nearly £10 billion to £42.6bn.
A rebellion of Tory MPs led by Chesham and Amersham MP Cheryl Gillan voted against the High Speed Rail (Preparation) Bill, but they were defeated by 325 votes to 37.
Aylesbury MP David Lidington did not take part in the vote, despite many of his constituents saying he should vote against it.
Mr Lidington, the European minister, said he would have had to resign from government and lose influence over key players if he voted against the plan.
Transport minister Patrick McLoughlin earlier told the Commons the new projected cost of HS2 had risen massively from its original £33bn estimated price-tag.
The new figure includes a £12.7 billion contingency fund.
The budget is made up of £21.4bn for phase one - from London to Birmingham through Aylesbury Vale - and £21.2bn for phase two.
Mr McLoughlin’s announcement came immediately after the latest spending review was unveiled, in which Chancellor George Osborne laid out £11.5 billion savings.
Stop HS2 Campaign Manager Joe Rukin said: “The casual way in which a 30% jump in the costs of HS2 has been announced by the transport secretary, which almost completely wipes out the cuts made in the spending review, is unbelievable.
“The DfT have always said the costs wouldn’t go up as there was an ample contingency built in, but now we know, like everything else which has been said about the case for HS2, that this was completely false.
“To push ahead with HS2 blindly because it sounds like it must be a good idea is simply insane and a kick in the teeth to everyone affected by the cuts.”
The HS2 bill now has to go through the committee stage in the Commons.