Groups fighting the Government's HS2 high-speed rail scheme will try to derail the £34 billion project with court challenges starting today.

If the judicial reviews are successful, the project could be put back by two years as fresh consultations will have to take place.

The first phase of HS2 would see a new, high-speed rail line running from London to Birmingham. The scheme has polarised opinion, with residents' groups and some councils opposing it, but supporters point out the benefits of a cut in journey times between the UK's two biggest cities.

Legal challenges are being brought by the HS2 Action Alliance and 51m, an alliance of councils, about alleged consultation failings.