The protesters, who are in a maze of tunnels 18 feet underground, said they wanted construction to stop until an "unbiased and open" public inquiry was held into the new A30 project including its design, building, and financial and operating systems. They also called for relevant documents to be open to public scrutiny, with financial details of the road to be revealed to the inquiry.
Later, the protesters' A30 Action group headquarters claimed that the Devon under sheriff had "gambled with life and limb" by cutting the five protesters' own communications link with the surface. The under-sheriff, Trevor Coleman, leading the eviction of the Fairmile camp on the route of the A30 near Exeter, rejected the claim and said their proposals were "totally unacceptable".
"They are unrealistic and I could not deliver on them anyway because I do not have the power to do so. I cannot negotiate," he said. Today, ground radar will be used by the authorities to map out the extent of the tunnels.
Speaking from below ground by citizens' band radio link, protester John Woodhams said that if their demands were not met "we will just hang in here as long as we possibly can in the hope he [Mr Coleman] will change his mind and save a lot of time and money".
The only female underground protester, known as Animal, warned: "We have got food and water to last almost indefinitely."
The Fairmile eviction is the third and last involving camps built over the last two and a half years in the path of the pounds 65m, 13-mile road scheme between Exeter and Honiton.
Stephen Langley, a surgeon at Southampton Hospital who yesterday descended the length of the protest tunnel so far cleared, said the protesters "appear to be very well with plenty of food and water. They could be down there for about a month, they have got enough supplies for that long".
Early yesterday, tunnelling specialists cut their way through a six- inch-thick steel-plated door leading into the protesters' tunnel, which is called Big Momma.
Mr Coleman said the tunnellers faced arrest when they finally came out. "They are obstructing me, I have been down the shaft and read them a specific warning relating to tunnelling obstruction and the cost." But he said it was "anyone's guess" how long it would take to get them out. "We still do not know the extent of the tunnel."
Video footage brought out by one of the tunnelling experts showed a second steel door, behind which there is believed to be a further network of tunnels. Meanwhile, work was continuing to remove three remaining protesters from trees on the site.