Minor scuffles broke out when one campaigner attached himself to some new equipment being delivered to help with the eviction.

Three campaigners were arrested after being released from chains inside a derelict cottage on the protest site near Weeford, Staffordshire, where the Birmingham Northern Relief Road is planned.

Protesters have moved into tunnels beneath the planned route of the motorway and say they have built a network of the most sophisticated tunnels seen at an environmental protest. Specialist underground search teams have been brought in to help evict them.

It follows the arrest on Tuesday of three men and one woman as bailiffs and police moved onto the site.

The four have been charged with obstructing the undersheriff during the eviction process and bailed on condition that they stay away from the site.

Protesters ready for battle

Protester Emily Price, 19, from Nottingham, said: "Everyone who is going underground is in position.

"The bailiffs have made considerable progress into the first tunnel. But we have food and water for 30 days. So far it's one down, 29 to go."

Protesters were in good spirits and determined to stay the course, she said.

Many veterans of the Manchester Airport and Newbury By-pass demonstrations are among the protesters. Eco-warrior leader Muppet Dave, 32, said his colleagues were ready and prepared for the bailiffs and police

"Everyone is ready, it is what we have been waiting for," he said.

On Tuesday tree-top protesters held officials at bay for several hours before being abseiled to the ground by specialist climbing teams.

The Assistant Chief Constable of Staffordshire, Steve Green, said he was impressed with his officers' operation, which had been conducted "as safely as it possibly could be".