Objectors remained defiant after the Court of Appeal rejected their latest challenges to Government plans to go ahead with the HS2 national high-speed rail project.
Fifteen councils and many other objectors, including residents' associations along the route, had asked the appeal judges to order further assessment of the scheme as a whole.
All grounds of challenge were dismissed, but anti-HS2 campaigners drew comfort from a split in the three-judge court on the key question of whether a full strategic environmental assessment (SEA) should have been carried out to assess the impact of both HS2 and its alternatives.
Two of the judges - Lord Dyson, the Master of the Rolls, and Lord Justice Richards - supported the Department of Transport's contention that an SEA under a European Directive was not required. But Lord Justice Sullivan disagreed and added the warning: "If, as I have concluded, an SEA is required and there has not been substantial compliance with the SEA Directive, it would be difficult to think of a more egregious breach of the Directive given the scale of the HS2 project and the likely extent of its effects on the environment."
Because of its public importance, the appeal court gave the objectors permission to bring a further appeal on the SEA issue before the Supreme Court, the highest court in the land. They also gave permission for a further appeal over a second EU Directive - the Environmental Impact Assessment Directive (EIAD).
Buckinghamshire County Council and other local authorities unsuccessfully contended that the parliamentary hybrid Bill procedure being used by the Transport Secretary to seek development consent for the two phases of HS2 was not capable of achieving the objectives of the EIAD - particularly ensuring full public participation in the decision-making procedures.
David Elvin QC argued on behalf of the objectors: "The level of parliamentary scrutiny in a proposed hybrid Bill would not meet the standard of scrutiny required by European law, given the all-party support for HS2 and the fact there would be a whipped vote".
Hilary Wharf, director of HS2AA, welcomed the court's decision to allow the Supreme Court to give a final decision on the scheme. She said: "It's a positive move and we are confident that, at the end of the day, the Government are going to have to do a strategic environmental assessment and take their environmental obligations seriously."
But High Speed Rail Minister Simon Burns said: "By dismissing all seven grounds of appeal and declining to refer the case to Europe, this is the second time in four months a court has rejected attempts to derail HS2. Parliament is the right place to debate the merits of HS2, not the law courts, and we will introduce the hybrid Bill for Phase One before the year is out.
"I urge opponents not to waste any more taxpayers' money on expensive litigation and instead work with us on making HS2 the very best it can be. We continue to move forward with the crucial business of getting the scheme ready for construction in 2017 and delivering enormous benefits for the country."