She successfully appealed to keep it closed after it was included on official maps showing areas open to the public under Right to Roam laws.

Now the Dartmoor National Park Authority plans to use its powers to reopen it by forcing Mrs Alford to allow access or through compulsory purchase.

Walkers have been warned to keep off the land.

Although the tor is private land, access was allowed by its previous owner for more than 30 years before Mrs Alford closed it.

When the land was included on Right to Roam maps, it was contested by Mrs Alford because her insurers said she could be liable if anyone was injured while walking or climbing.

She used the Human Rights Act to attempt to deny walkers access, an argument upheld by planning inspectors.

But now the park authority will first ask Mr Alford to voluntarily allow access. If she refuses, it will use its statutory powers to enforce access or failing that carry out a compulsory purchase of the tor.

Nick Atkinson, chief executive of of the park authority, said he hoped that an arrangement could be reached.

He said: "It is a much-loved tor. It's the essence of the park and I think access can be achieved there in a non-damaging way which can benefit the owner."

Vixen Tor was a popular spot for walkers for over 30 years.

Any purchase would be a highly unusual move, but walkers have welcomed the plan.

John Skinner of the Ramblers' Association said: "It's very much part of the Dartmoor scope and culture, and people should be allowed to see it and make use of it."

Mrs Alford told the BBC she thought that "this is supposed to be a democracy".

She said: "Similar inspectors' decisions have been respected elsewhere in the country. It ought to be here."

The park authority hopes to see the tor reopened to the public by the end of the year.