THE UNITED Nations World Heritage Committee has called on the Government to block plans for the supermarket development set to revitalise Hayle's South Quay.
And the influential conservation body has also threatened to put the site on its World Heritage in Danger list if the Government does not comply.
The UN committee met in Cambodia last night and agreed to issue a number of edicts on the valuable World Heritage Site status conferred on Cornwall and Devon's historical mining areas.
These included raising concerns about the resumption of mining at South Crofty tin mine and calling for no resumption of mining there while they investigate plans.
But crucially they also said the UK Government should block the proposed building of a supermarket, restaurant and other units in the Hayle harbour area and insist on smaller developments instead.
A statement issued this morning said: "The World Heritage Committee regrets that [the UK Government] has not complied with the request expressed by the Committee [in 2012] to halt the Hayle Harbour project, and, given that planning permission has already been granted, strongly urges the [Government] to halt the development of Hayle Harbour in the light of its potential impact on the Outstanding Universal Value of the property and to consider, as a matter of urgency, all possible ways to develop alternative solutions for smaller-scale heritage-led regeneration for the Hayle Harbour site that respect its role as the port and harbour for the mining industry"
The committee said that if development was not halted in Hayle harbour and reconsidered, they would "consider inscribing Cornwall and West Devon Mining Landscape (United Kingdom of Great Britain and Northern Ireland) on the List of World Heritage in Danger at its 38th session in 2014."
The move has prompted a swift response from the Cornish Mining World Heritage Site (CMWHS) Partnership Board, who expressed "concern" at the UNESCO decision.
CMWHS say the UN committee made its decisions without even discussing the issues last night.
The group said they had worked hard to produce a management plan, endorsed by the Government and local councils to ensure "internationally important historic mining features are carefully preserved for future generations."
The statement said: "The UK Government, as a signatory to the World Heritage Convention, and local councils, as the planning authorities, are required to protect World Heritage Sites from inappropriate development.
Julian German, chairman of the Partnership, said: "We are disappointed by the decisions, particularly as the original report from UNESCO's advisory bodies contained a number of errors and misunderstandings which we were not given the opportunity to challenge.
"The UK Government have confirmed that it will not ask Cornwall Council to rescind planning consent for either South Crofty or the supermarket on South Quay, Hayle Harbour."
He added: "The Partnership note that the report to the World Heritage Committee acknowledged the substantial danger for this area of the Site posed by flooding, and the risk of the loss of authenticity should the current silting of the harbour render it redundant as a working port.
"Given these wider risk factors, we welcome the proposed mission to allow a fuller, more detailed consideration of the challenges and issues affecting Hayle Harbour, and how the consented supermarket scheme addresses these.
"We will continue to work closely with the planning authority, landowners and the Government to ensure that the mission has access to, and considers, all the relevant information, to enable it to take a balanced decision."
Planning permission has been granted to the owner of South Quay, Dutch firm ING, to build a new supermarket, 30 homes, a waterfront restaurant and shops on the area, which has been derelict for 30 years.
ING are thought to be in discussion with ASDA.
