Government funding for England's much-loved national parks is on track to fall by two-fifths by the end of the decade, new analysis shows.
Sharp cuts to the annual grants for most of the protected landscapes under the coalition were followed by a pledge by the last Conservative government to protect funding for English national parks up to 2020.
But analysis of figures given to the Press Association in response to a Freedom of Information request suggests that most parks will have suffered a real-terms fall of more than 40% in funding from 2010 to 2020.
The assessment examined the funding settlement between 2016 and 2020 for each park, set out by then environment minister Rory Stewart in a letter to National Park Authorities in January 2016, and compared it to previous annual grants.
It uses Treasury forecasts for inflation to track the change in grant levels for all 10 national parks from 2010 to 2020.
The analysis finds funding for eight of the parks, including the Lake District which has just been designated as a World Heritage Site, could be roughly 43% below 2010 levels by the end of the decade once inflation has been taken into account.
Despite seeing its size increase by a quarter, the Yorkshire Dales National Park is likely to suffer a real-terms fall in funding of almost a fifth (19%) over the 10-year period.
Only the South Downs National Park, the youngest national park which was created in April 2010 and received a significant rise in funding in 2011 to help it establish itself, could be better off in real terms over the decade, with funding up 20%.
In addition to cuts for most parks before 2015, they all face a further squeeze from rising inflation, which is now well above the 1.72% the Government used to calculate the annual rise in the settlement from 2016-2020 as it sought to protect funding.
The Campaign for National Parks chief executive Fiona Howie said the analysis was "deeply concerning".
She said funding cuts between 2010 and 2015 led to closure of information centres, an end to much of the work on keeping rights of way open and a halt to efforts by some parks on flood defence, conservation and climate change mitigation.
To meet Government ambitions for national parks to take the lead on connecting young people with nature, promoting sustainable tourism and tackling threats such as flooding, they needed to be properly and sustainably resourced.
"The National Parks are inspiring and breathtaking areas of our country.
"They provide many public benefits including being part of our shared cultural heritage, being important for wildlife and benefiting the nation's health and well-being.
"They also play an important role in our rural economy; they are visited by millions of people each year, generating over £4 billion annually through tourism and support around 70,000 jobs.
"They need to be properly valued by the Government and supported financially," she said.
An Environment Department (Defra) spokeswoman said: "We recognise the value of our National Parks - both to our cultural identity and our economy - which is why we have increased their budgets each year since 2015 and allocated extra funding for the Lake District and Yorkshire Dales."