The High Court has thrown out a last ditch legal challenge to bring a judicial review into a planned new Bexhill to Hastings link road.
It means that work on the new road is likely to now begin in January.
Funding for the £56million road was approved by the Department for Transport in March but campaigners say it will destroy a large part of the countryside. They say they will consider direct action to stop it being built.
Councillor Peter Jones, leader of East Sussex County Council, said: "We're delighted by today's decision and that the High Court has recognised there was no basis for this legal challenge.
"It means we can now get on and really make a positive difference to the most deprived local economy in the South East.
"This road is absolutely crucial to the regeneration of Hastings and Bexhill for people and businesses. It'll bring better access to jobs; opportunities for housing and business development; and fewer cars using roads that aren't suitable for them."
Last month, the Government confirmed the Compulsory Purchase Orders, meaning the Council can now acquire the land needed for the road and for new environmental habitats.
In response, campaigners from the Coombe Haven Defenders, organised a weekend on a site on the route of the road to plan action to stop it going ahead.
They claim that there will be an adverse impact on the area's badgers, bats, dormice on a site that has been identified as a Site of Special Scientific Interest.
A last ditch bid to win a judicial review over the decision was brought by the Hastings Alliance. It described the plans as the 'worst of the hundreds of new roads planned by Chancellor George Osborne'.
Environmental work, including archaeological surveys and creating new habitats for wildlife, began in July.
In April, East Sussex County Council's Cabinet agreed to allow an early start to work on the road before final funding approval is received.