Video report by ITV News Science Editor Tom Clarke

The group charged with protecting England's areas of natural beauty has been accused of neglecting them.

Natural England, a government body, is responsible for ensuring more than four thousand sites of special scientific interest (SSSI) are clean and well kept.

But many have been left at the mercy of fly-tippers, invasive plants and chemical pollution which are a danger to native plants and wildlife.

Brent reservoir is one such designated site, but it has been left up to local residents to clear up the beer cans, plastic bags and mattresses that blighted the area.

Natural England is charged with inspecting SSSIs sites, such as Brent, every site years, to ensure they are still supporting the wildlife that inhabit these biodiversity areas.

Many important wildlife sites have been left at the mercy of fly-tippers. Credit: ITV News

But a new report from Greenpeace found that many parts, including areas in the Pennines, Exmoor and the Lake District have not been monitored in eight to 10 years despite showing signs of neglect.

England’s highest mountain, Scafell Pike was last assessed in 2010.

Campaigners blame government cuts to Natural England's budget for the group's failure to deliver on its pledge to reverse the decline of species across the UK.

The Lake District. Credit: PA

Rebecca Newsom, head of politics at Greenpeace UK, said: “The government must end this shameful neglect of England’s most important nature sites. Funding cuts must be reversed and a new environmental watchdog with proper enforcement and investigation powers established, to avoid systematic failures like this after Brexit.”

In a statement, DEFRA told ITV News it was committed to protecting SSSIs as part of the government's 25 year plan for the environment.