Legal action is being taken over plans to transform a Lake District quarry into a heritage tourism attraction.
The proposals from Burlington Slate and Zip World for Elterwater Quarry were given the go-ahead by the Lake District National Park Authority last month.
It is predicted to attract up to 50,000 visitors a year.
It will include an underground cavern explorer experience, using zipwires. Plans include installing platforms in the caves at points of interest. Visitors will travel from one platform to another via zipline.
Now, Friends of the Lake District has revealed it is taking legal action.
The bid last month was a revised application for the scheme – members of the committee had previously rejected the proposal, largely because of the increase in traffic.
The revised proposal included a revised travel plan, which encourages people to walk, cycle and use public transport to reach the site.
Proposals include providing an improved no 516 bus service or operating a private Zip World shuttle bus from Brockhole.
Zip World would also financially reward customers that have used non-car travel to make all or part of their journey to the experience through ticket pricing.
But Friends of the Lake District said the plan remained inadequate.
It said: “The development would cause significant harm to the character of the area and the local community. Even a small increase in traffic in this sensitive landscape could have a big impact.
“The charity has concerns about the lawfulness of the decision in respect of the understanding of the Sandford Principle, the enforceability of the travel plan, and the assessment of the effects on the tranquillity of the landscape.”
It is seeking a judicial review of the committee’s decision.
Michael Hill, CEO of Friends of the Lake District, said: “Our charity has always acted as a ‘critical friend’ to the Lake District National Park Authority.
“We work in close partnership with them on many important issues, and in our recent manifesto we called for their funding to be doubled. As a friend, we believe we need to speak up when decisions are made which put this precious landscape under threat.
“That is why we have asked for the High Court to review the lawfulness of the approval of this adventure attraction.”
The charity said it believed the development would cause great harm to the character of the valley. It added that 90,000 people signed a petition against the development at pre-application stage, and both the local parish council and ICOMOS, the UNESCO body set up to monitor World Heritage sites, also opposed it.
ICOMOS said the development risked undermining the landscape qualities of the valley; that Lakeland’s quarrying history would be trivialised, and that permission should not be granted.
A spokesman for the Lake District National Park Authority said: “A planning decision notice granting permission for development at Elterwater Quarry subject to conditions was issued on May 3.
“We were made aware June 18 that a claim for judicial review had been made to the High Court. We have yet to receive any sealed documents. The authority will not comment on ongoing legal proceedings.”
Who are Friends of the Lake District?
Landscape charity Friends of the Lake District dedicates itself to protecting and enhancing the environment.
Founded 90 years ago in Keswick, it can be a controversial charity – and we have given it the opportunity to answer its critics.
