There are three Principles for Access which govern the National Trust's management in the countryside:

Principle 1: The duty and primary purpose of the National Trust in the countryside is to promote permanent preservation for the benefit of the nation. It will regard access as a fundamental way of providing this benefit and as a principal purpose.

Principle 2: The National Trust Acts establish its responsibilities for conservation. If serious conflict arises, conservation will take precedence over access.

Principle 3: The National Trust will ensure that the countryside retains characteristics which afford the widest range of experiences and will enable people to enjoy access to its properties.

For more information see Open Countryside or Recreational Activities at National Trust Properties