The influential committee has said that the government’s definition of sustainable development, upon which some of the more controversial elements of the bill hinge, should be "articulated more clearly…because it will be used as a material consideration in planning decisions and might have to be tested in the courts".

The committee concluded that the NPPF should stress the importance of the social and environmental as well as economic aspects of sustainable development to ensure that “there is no potential for confusion about the equal importance of all three" and to prevent the economic dimension being seen as predominant.

A letter to the Prime Minister following the committee’s deliberations suggested that the consideration of “sustainable development” should include food resilience, energy, climate change and some waste management functions – as well as how the aims of the natural environment White Paper for designating green spaces, Local Improvement Areas and wildlife corridors would be progressed.

It also wants the NPPF to specify how a duty-to-cooperate on such issues, as well as on developments on the boundaries between local authorities, would operate and be enforced.

The committee also said that the NPPF was "unsatisfactory" because it presents different messages to different audiences about what the presumption in favour of sustainable development actually means in practice where Local Plans are not properly in place or silent on any particular proposal. [see earlier story]