“ Wade & Forsyth, Administrative Law , 10th ed (2009), pp 315–316 states that the principle that policy must be consistently applied is not in doubt and that the courts now expect government departments to honour their statements of policy. Policy is not law, so it may be departed from if a good reason can be shown.”
“The lawful exercise of [statutory] powers can also be restricted, according to established principles of public law, by government policy and the legitimate expectation to which such a policy gives rise.”
“Where a public authority has issued a promise or adopted a practice which represents how it proposes to act in a given area, the law will require the promise or practice to be honoured unless there is good reason not to do so. What is the principle behind this proposition? It is not far to seek. It is said to be grounded in fairness, and no doubt in general terms that is so. I would prefer to express it rather more broadly as a requirement of good administration, by which public bodies ought to deal straightforwardly and consistently with the public.” 30 Thus, in R (WL (Congo)) v Secretary of State for the Home Department[2012] 1 AC 245 (in which this court reversed the decision of the Court of Appeal but without doubting the observation in para 58 for which I have cited the decision in para 29 above), Lord Dyson JSC said simply, at para 35: “The individual has a basic public law right to have his or her case considered under whatever policy the executive sees fit to adopt provided that the adopted policy is a lawful exercise of the discretion conferred by the statute.”
“it is a well established principle of public law that a policy should not be so rigid as to amount to a fetter on the discretion of decision-makers.”