The general requirements would be that the organisation had to be subject to the authority or control of the state, whatever its legal form, and whether in public or private hands.
... unconditional and sufficiently precise provisions of a Directive could be relied on against organizations or bodies which were subject to the authority or control of the State or had special powers beyond those which result from the normal rules applicable to relations between individuals.
It follows...that a body, whatever its legal form, which has been made responsible, pursuant to a measure adopted by the state, for providing a public service under the control of the state and has for that purpose special powers beyond those which result from the normal rules applicable in relation between individuals, is included... among the bodies against which the provisions of a directive capable of having direct effect may be relied upon.The women appealed to the House of Lords.
In the meantime, the European Court of Justice held that Art.5(1) could be relied on against anyone made responsible for the provision of a public service.
Held, allowing the appeal, that the corporation was a body against which Art.5(1) could be enforced; the matter would be remitted for assessment of compensation (Foster v British Gas Plc (C-188/89) [1991] 1 Q.B.