Campaigners have vowed to continue the fight to stop HS2 going ahead, despite the fact that a Conservative election victory should ensure a smooth path for the £50 billion high-speed rail project, which will connect London with Birmingham as well as Manchester and Leeds.
An HS2 Hybrid Bill is going through Parliament with royal assent expected in December 2016 and work on the first phase, from London to Birmingham, due to start in 2017 for completion in 2026.
A second, Y-shaped route extending the line north of Birmingham to Manchester and Leeds is due to be finished around 2032/33.
Labour has been supportive of the project, but if the party had regained power in the election, its ministers were likely to have taken a close look at the cost of the scheme and also considered whether phase two was feasible.
Former shadow chancellor Ed Balls warned there would be "no blank cheque" for HS2.
Phase one will see a high-speed line going through Tory heartlands in the Chilterns where many residents and local councils are bitterly opposed to the project.
The project could also face difficulties in its passage through the House of Lords.
A recent report by the House of Lords Economic Affairs Committee said the Government had not yet made a convincing case as to why HS2 was necessary.
The committee added that the last Government set out two main objectives for HS2 - increasing capacity on the railway and rebalancing the economy - but had failed to make a convincing case for either.