The partly demolished Cornwall Coliseum, Carlyon Bay, which Commercial Estates Group is planning to redevelop into a multimillion-pound resort The Beach. Photo: Brian CC-BY-SA-2.0

Campaigners are urging a council to take action to force developers to clear obstructions partly blocking a national trail.

The Open Spaces Society said a fence and portable cabin on the site of the South West Coast Path at Carlyon Bay, Cornwall, restrict use of the path and should be removed.

The area is the site of a planned £250m development by Commercial Estates Group on the site of the old Cornwall Coliseum, which has stood derelict for some years. A section of the South West Coast Path, the 630-mile trail that runs from Poole in Dorset to Minehead in Somerset, overlooks the development site.

Local campaigner Gloria Price, a member of the Open Spaces Society, has been pressing for the removal of the obstructions for years.

OSS general secretary Kate Ashbrook said: “We have today written to Cornwall Council’s rights-of-way department, urging it to take legal action to remove the obstructions.  It is in fact a very special path, the South West Coast Path national trail, used and enjoyed by thousands of people each year.

“Cornwall Council has a legal duty to ensure this path is open to its full width and in good order. The path has been made narrow and off-putting by the fencing and portable cabin. They are a physical and a psychological barrier to the public.”

In February this year, a High Court judge ruled that gates at Barcroft Hall in Somerset be removed from a right of way. The gates were unlocked but Mr Justice Cranston said: “There is no reason to confine interference to physical interference. An object can get in the way of the right of passage or other amenity rights because of its psychological impact.”

The OSS contends the whole width of the South West Path should be available to walkers. “The council should serve a legal notice on the developers requiring them to reopen this flagship footpath to its full width,” Ms Ashbrook said.

Gloria Price added: “The South West Coast Path has been obstructed by the developer, and while we have been writing to Cornwall Council since 2004, no action has been taken by the council properly to resolve this matter.  It needs to be resolved urgently, for the future of public access in Cornwall.”

But Jon Kenny, development director of the Commercial Estates Group, said: “We are puzzled about this because we have discussed it with Cornwall Council to ensure we have clarity and our land documentation shows the definitive route is free from obstruction.

“The route that the council has signposted across the top car park is also clear.”

Carolyn Bay, 3km (2 miles) east of St Austell, is the site of the former Cornwall Coliseum, a former venue for rock gigs and other entertainment, but now an unsightly ruin.

The proposed Commercial Estates Group proposals to build more than 500 properties across two bays have been mired in planning disputes for years. The company’s latest plans involve a ‘more Cornish design’ for the resort’s buildings, and a more car-free environment.