The duty to cooperate was created in the Localism Act 2011, and amends the Planning and Compulsory Purchase Act 2004. It places a legal duty on local planning authorities, county councils in England and public bodies to engage constructively, actively and on an ongoing basis to maximise the effectiveness of Local and Marine Plan preparation in the context of strategic cross boundary matters.
In July 2018 the four Black Country Authorities sent out letters to the surrounding Local Authorities regarding the issue of housing and employment need across the Black Country and how it can be met. The letter asked the Local Authorities to provide an update regarding their strategic plan making. Specifically their local plan review status and whether they would be able and willing to accommodate any housing and employment developments arising from the Black Country.