Morwellham Quay, part of the Cornwall and West Devon mining areas which hold World Heritage status, was put into the hands of administrators in September. Devon County Council, which had already advanced it £1.2-million in support refused to grant further subsidy from taxpayers' money.

Chartered accountants and management consultants Grant Thorton, the administrators of the Morwellham and Tamar Valley Trust, instructed international property agents King Sturge to market the site and its attractions as a going concerned at a guide price of £1.1-million. Final bids had to be submitted to the property agents by today (Thursday).

Joint administrator Nigel Morrison, a partner in Grant Thorton, confirmed that there had been considerable national interest' in the site.

He told the Times: 'Once the deadline is past we will get together with representatives from King Sturges to consider the bids and form a view of what is the best one, which would not necessarily mean the highest bid.'

Mr Morrison said it was not 'a straightforward property sale' as there were many legal questions appertaining to the sale, especially over the conditions of publically funded grants already secured.

He said it could be around two weeks before a decision is made. The administrators will meet representatives from West Devon Borough Council and the county council next week to consider the options.

The Heritage Lottery Fund (HLF) awarded a grant of £2,331,000 to the borough council for the Tamar Valley Mining Heritage Project in October 2006. To date, £1.5-million of this grant has been released by the HLF.

The Morwellham and Tamar Valley Trust was an important partner in the Tamar Valley Mining Heritage Project, with conservation works and the construction of a new orientation centre planned to take place at the quay.

Nerys Watts, head of HLF South West, told the Times: 'This is a really unfortunate situation. Since Devon County Council's withdrawal of funding — and Morwellham and Tamar Valley Trust subsequently going into administration — HLF has been working closely with West Devon Council to identify options that will enable them to meet the aims of the project with other investors or partner organisations.

'It is hoped that together we can find a solution, but if this is not possible HLF may require that all or part of the grant be repaid.'

If Morwellham is not run by a charitable trust or body but by a commercial organisation and there was no longer a museum attraction then the Devon taxpayers could well be left to repay that seven-figure grant.

Michael Stone, the ex-chair of the trustees, said: 'I, personally, would like to see some form of trust or charitable body, such as its previous one, and the assets of Morwellham retained by that trust, which would maintain the site for the benefit of West Devon and the general public.'

Mark Horton, professor of archaeology at the University of Bristol and who has presented a television documentary on Morwellham in the BBC's Inside Out programme, said he was in no doubt that 'Morwellham Quay lies at the very top end of the spectrum of heritage assets in the UK'.

He added: 'Indeed, without Morwellham, the West Devon element of the World Heritage site is pretty meaningless, and its loss would to my mind, severely jeopardise the inscription.'

If the Morwellham site was to be disposed of, it would trigger an immediate 'at risk' alert — the first stage of removal by UNESCO, he said.

Prof Horton said this was 'no idle threat' as UNESCO had withdrawn status to Dresden in Germany after it had constructed a road link over a river.

Prof Horton, who is also well known as a presenter on the BBC TV series 'Coast,' told the Times: 'I have no particular axe to grind but what I'm greatly concerned about is the threat to one of the region's important heritage sites.'

* See next week's Times for a feature on the Garlandstone, the historic vessel moored at Morwellham Quay.