Thirlmere, site of the proposed activity hub. Photo: Mike Prince

Leading conservation charity the National Trust has said it will object to the planned zipwire at Thirlmere.

Men Behaving Badly actor Caroline Quentin, who is president of the Campaign for National Parks, has also voiced her opposition to the proposals for an activity hub at the Lake District site.

The trust pointed out its roots lay in the Thirlmere area and said the zipwires would have an adverse impact on the environment, generating levels of activity and noise at odds with the valley’s tranquil character.

It added the recently achieved world heritage site status had not been adequately considered in the proposals.

Tree Top Trek, which runs a high wires facility at Brockhole near Windermere, wants to install twin four-line zipwires across the lake and upgrade existing cycle tracks in the area.

The trust said: “The National Trust has been looking after special places in the Lake District on behalf of the nation for the past 120 years. It’s our birthplace, our spiritual home, somewhere we care deeply about.

“It’s here that we look after over 20 per cent of the Lake District national park.

“The land we manage in the Thirlmere Valley is around the high fells, approximately 1.5-2km from the proposed Thirlmere activity hub and zipwire installation.

“The Thirlmere valley was one of the key locations for the development of the early conservation movement in the Lake District. It inspired our founders to form the National Trust – it’s one of our birthplaces – and this is recognised in the world geritage site inscription.

“Just as our founders did all those years ago, we’re standing up for the Lake District here, as we recognise this development could have a significant impact on the future of this landscape.

“We can see that elements of the proposed development would bring some benefits to the area with plans for improved cycle infrastructure and employment opportunities. However, the application raises significant issues of principle for the trust, therefore we are objecting to this planning application.”

Caroline Quentin, president of the Campaign for National Parks. Photo: CNP

Ms Quentin said: “I’m concerned about the proposed zipwires in Thirlmere. My fear is that they will spoil the peace and tranquillity of this beautiful, important place. I am all for development that enhances our national parks but my instinct is that we should say no to zipwires in Thirlmere.”

The Campaign for National Parks has submitted a letter of objection to the Lake District National Park Authority and is urging members of the public to do the same.

Ruth Bradshaw, policy and research manager at the Campaign for National Parks, said: “Thirlmere is considered the birthplace of the conservation movement in the UK. These proposals are a serious threat to the calm and tranquillity of this beautiful place.

“We are also extremely concerned at the precedent this sets for further commercial activity in this valley, elsewhere in the Lake District, and in other national parks.”

The Friends of the Lake District said national parks should be for the many, not the few.

It said: “This is a test case that will determine whether the Lake District National Park Authority is in the business of protecting our nationally important landscapes or warming to the idea of commercial tourist development in beautiful open countryside where it does not currently exist.

“A national park’s protection is based on the planning laws and guidelines that it is required to abide by. National park and world heritage site status both bring a responsibility to adhere to a set of values to protect the special landscapes in these areas.

The Friends, a landscape charity, said Tree Top Trek’s application disregards planning law and policies that are in place to afford a national park the highest levels of protection from development.

“The decision of the national park’s planning board on whether to recommend refusal of this planning application is guided by these policies so why is there a sense of unease amongst those opposed to this application?” it said.

“It is perhaps because the outcome of this application could have major consequences for the future of all of our national parks. Many view this application as a potential Trojan horse, both for further development at Thirlmere and as a green light for large-scale commercial development in all of our national parks.”

The organisation’s planning officer Laura Fiske said: “Friends of the Lake District is convinced that there is no justification for this development in this sensitive location and it should be refused.

“The country’s most spectacular places must remain free and open for all to appreciate and enjoy. National parks must be managed for the interests of the many and not the few.

“The size and scale of this application at 39ha – equivalent to 28 football pitches – means that the national park planning authority must treat this as a ‘major development’ and adhere to national and its own local policy introduced to protect the park’s most valuable assets including the Thirlmere valley from large-scale commercial developments.

“We are demanding that the principles and policies introduced by Parliament to protect all of our national parks from damaging development must be upheld.”

Other organisations objecting to the proposals include the British Mountaineering Council, the Wainwright Society and the Open Spaces Society.

The Lake District National Park Authority has extended the deadline for submissions to 12 January 2018.