As indicated above, the concept of 'public authority', both core and functional, was reviewed by the House of Lords in Aston Cantlow, which was decided after Poplar and Leonard Cheshire. (Although note that these cases were not specifically overruled by the House of Lords.) The House of Lords stressed that it was the nature of the function being performed that should determine whether a body was a functional public authority. Lord Nicholls suggested that there should be a 'generously wide' interpretation of public function so as to further the statutory aim of promoting human rights protection. Lord Hope stated that the concept of a functional public authority:

'… has a much wider reach, and is sensitive to the facts of each case. It is the function that the person is performing that is determinative of the question whether it is a … "hybrid" [functional] public authority.'

Lord Nicholls (para 12) suggested that the following factors may be relevant in assessing whether or not the relevant function is a public one:
(a) the extent to which, in carrying out the function, the body is publicly funded; or
(b) exercising statutory power; or
(c) taking the place of central government or local authorities; or
(d) is providing a public service.