And the protestors opposed to operations at Backdale Quarry near Bakewell have warned this could set their fight back several years.

The Peak District National Park Authority is preparing for the inquiry that will decide if it was right to serve an enforcement notice against quarrying firm MMC Mineral Processing and site owners Bleaklow.

The authority believes the firms have been removing more limestone than their planning permission allows.

They invited rural affairs minister Jim Knight to the quarry in January and he pledged his support for their fight to stop quarrying at Backdale.

But a special meeting has now been called as the government's planning inspectorate decides whether the enforcement notice is so legally unsound that it can be deemed "null".

If that is the case the inquiry, set to begin on April 4 in Calver, will be cancelled and work can begin again at Backdale.

It follows a recent case in Wales where a similar notice was ruled to be null.

Protestor Malcolm Wootton said: "Basically if it's a nullity then everything falls.

"The enforcement notice doesn't exist. The stop notice doesn't exist. The Peak Park may have to start the whole cycle again and the chances are there'll be two more years of damage before it gets to another appeal.

"It is clear that the authority is quite nervous. It is the toss of a coin as far as I'm concerned and an awful lot of money could be wasted."

In their legal submssion to the Planning Inspectorate, MMC's lawyers argue part of the enforcement notice is "is woefully vague and falls well short of the test for nullity".

And Bleaklow's submission concludes: "(The) PDNPA cannot reasonably argue that a notice is valid under Part VII of the 1990 (Town and Country Planning) Act, while at the same time acting contrary to the clear intentions of that Part."

MMC declined to comment ahead of the inquiry.

The planning authority meets tomorrow at Bakewell Town Hall to decide what it will do if the planning inspectorate rules against it.

A spokesman for the Peak Park said: "This issue is now in the hands of the planning inspectorate.

"We are keen for it to be resolved as quickly as possible and hope that by Friday the position will be clearer and our members can agree a way forward."