The director general of the National Trust has appealed to the government for greater clarity over the future of the Stonehenge road proposals.
Planners want to run the A303 in a tunnel past Stonehenge
Fiona Reynolds has sent an open letter to Transport Secretary Alistair Darling asking for more information about how decisions will be reached.
A public inquiry into plans to cover over the nearby A303 were completed nine months ago.
The letter points out a decision was due in September 2004.
Ms Reynolds said: "At this critical juncture there are worrying signs that the government is not giving the project the priority that its national and international status merits.
"Early indications were that it would be delivered, in September, but it appears we are still waiting."
The letter goes on to plead with the government not to allow the project to become obscured in "bureaucratic long grass".
Planners want to take the A303 under the World Heritage Site to reduce traffic congestion around the stones and improve visitor facilities
The proposed 2.1km (1.3 mile) tunnel would cost almost £200m.