England's national parks have produced a briefing note outlining how they support rural communities and economies.

Sustainable development is a fundamental principle underpinning much innovation and best practice, says National Parks England - the association which looks after the 10 National Parks in England.

"It is about enabling development that benefits people, the environment and the economy simultaneously," it says.

"Our Vision for National Parks is for them to be places where 'sustainable development can be seen in action'."

National Parks are already significant economic assets, says the association.

More than £10.4bn of turnover being generated annually by the 25,500 businesses that call England's National Parks their home, it says.

"With a combined GVA of £6bn, National Parks make a significant contribution to the national economy – similar to that of a city such as Plymouth or Swindon.

"National Park economies are reliant on sustaining these high quality environments. Those economies can in turn help to maintain and enhance these special places."

The briefing note can be downloaded here.