THE Court of Appeal is due to rule on 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, want the appeal judges to order further assessment of the scheme as a whole.

The objectors say it will cost far too much to get HS2, as currently envisaged, up and running from London to Birmingham, Manchester and Leeds. They estimate £58 billion and rising. The official all-contingency cost of the project has recently climbed from £33 billion to £42.6 billion.

Former Labour cabinet minister Lord Mandelson, ex-Chancellor and former Transport Secretary Alistair Darling, and ITV chairman and former Tory MP Archie Norman have all cast doubt on the scheme in recent weeks. But Prime Minister David Cameron has reiterated his support for the project.

The objectors say the project will cause an unacceptable level of environmental damage, loss of homes and disruption to many communities - without the public having had a fair hearing and a chance to suggest reasonable, cheaper alternatives.

David Elvin QC, appearing for HS2 Action Alliance (HS2AA), told the appeal court the project had already blighted a swathe of properties along the route. He argued it had been given the go-ahead in breach of EU rules requiring a strategic environmental assessment (SEA).

It was being seen as the country's largest infrastructure project for a generation and the largest single rail project since the 19th century. But the decision in principle to proceed, taken by the Transport Secretary in January last year, breached a European Directive requiring an SEA.

He asked three judges - Lord Dyson, the Master of the Rolls, Lord Justice Richards and Lord Justice Sullivan - to overturn a High Court ruling in March.

Mr Elvin argued High Court judge Mr Justice Ouseley had taken "too restrictive" an approach to the directive when he held that Parliament should be left free to decide on the scheme.

A Department for Transport spokesman said: "It is unfortunate but inevitable that opponents of HS2 will do whatever they can to delay the Government's plans, but the Government remains committed to delivering HS2 as quickly as possible."

© Press Association 2013