"An order, even if not made in good faith, is still an act capable of legal consequences. It bears no brand of invalidity upon its forehead. Unless the necessary proceedings are taken at law to establish the cause of invalidity and to get it quashed or otherwise upset, it will remain as effective for its ostensible purpose as the most impeccable of orders."
"It would ... be inconsistent with the doctrine of ultra vires as it has been developed in English law as a means of controlling abuse of power by the executive arm of government if the judgment of a Court in proceedings properly constituted that a statutory instrument was ultra vires were to have any less consequence in law than to render the instrument incapable of ever having had any legal effect."
" ... Lord Diplock confirmed that once it was established that a statutory instrument was ultra vires, it would be treated as never having had any legal effect. That consequence follows from application of the ultra vires principle, as a control on abuse of power; or, equally acceptably in my judgment, it may be held that maintenance of the rule of law compels this conclusion."
"This is the essential constitutional underpinning of the statute based part of our administrative law. Nevertheless, I accept the reality that an unlawful byelaw is a fact and that it may in certain circumstances have legal consequences. The best explanation that I have seen is by Dr Forsyth who summarised the position as follows in 'The Metaphysic of Nullity -- Invalidity, Conceptual Reasoning and the Rule of Law' [in Forsyth and Hare (editors), The Golden Metwand and the Crooked Cord, 1998] at page 159: 'It has been argued that unlawful administrative acts are void in law. But they clearly exist in fact and they often appear to be valid; and those unaware of their invalidity may take decisions and act on the assumption that these acts are valid. When this happens the validity of these later acts depends upon the legal powers of the second actor. The crucial issue to be determined is whether that second actor has legal power to act validly notwithstanding the invalidity of the first act. And it is determined by an analysis of the law against the background of the familiar proposition that an unlawful act is void.'"
"The truth is that the court will invalidate an order only if the right remedy is sought by the right person in the right proceedings and circumstances. The order may be 'a nullity' and 'void' but these terms have no absolute sense: their meaning is relative, depending upon the court's willingness to grant relief in any particular situation ... the problems of nullity are soluble by the formulation of principles and by their logical application, not by abandoning the field to free discretion."
"An important step in developing a principled and practical approach to these conundrums has been the development of the theory of the second actor. This theory, which has attracted significant judicial support, seeks to explain how an unlawful and void administrative act may nonetheless have legal effect. It is built on the perception that while unlawful administrative acts (the first acts) do not exist in law, they clearly exist in fact. Those unaware of their invalidity (the second actors) may take decisions and act on the assumption that these (first) acts are valid. When this happens the crucial question is whether these latter, or second acts, are valid."
"The central question raised here is whether these constables were acting tortiously in arresting the plaintiffs or whether instead they enjoy at common law a defence of lawful justification. This question, as it seems to me, falls to be answered as at the time of the events complained of. At that time these byelaws were apparently valid; they were in law presumed to be valid; in the public interest, moreover, they needed to be enforced. It seems to me one thing to accept, as I readily do, that a subsequent declaration as to their invalidity operates retrospectively to entitle a person convicted of their breach to have that conviction set aside; quite another to hold that it transforms what, judged at the time, was to be regarded as the lawful discharge of the constable's duty into what must be later found actionably tortious conduct ... I see no sound policy reasons for making innocent constables liable in law, even though such liability would be underwritten by public funds."
"Is a man to be sent to prison on the basis that an order is a good order when the court knows it would be set aside if proper proceedings were taken?"
"It would be a fundamental departure from the rule of law if an individual were liable to conviction for contravention of some rule which is itself liable to be set aside by a court as unlawful."
"They were concerned with administrative acts specifically directed at the defendants, where there had been clear and ample opportunity provided by the scheme of the relevant legislation for those defendants to challenge the legality of those acts, before being charged with an offence."