“ Thus having established, as I hope, that the plain and natural meaning of the words “has reasonable cause” imports the existence of a fact or state of facts and not the mere belief by the person challenged that the fact or state of facts existed, I proceed to show that this meaning of the words has been accepted in innumerable legal decisions for many generations, that “reasonable cause” for a belief when the subject of legal dispute has been always treated as an objective fact to be proved by one or other party and to be determined by the appropriate tribunal. ”

“ But in a time of emergency when the life of the whole nation is at stake it may well be that a regulation for the defence of the realm may quite properly have a meaning which because of its drastic invasion of the liberty of the subject the courts would be slow to attribute to a peace time measure. The purpose of the regulation is to ensure public safety, and it is right so to interpret emergency legislation as to promote rather than to defeat its efficacy for the defence of the realm. ”

“ In the first place, it is important to have in mind that the regulation in question is a war measure. This is not to say that the courts ought to adopt in wartime canons of construction different from those which they follow in peace time. The fact that the nation is at war is no justification for any relaxation of the vigilance of the courts in seeing that the law is duly observed, especially in a matter so fundamental as the liberty of the subject — rather the contrary. ”

“ When it comes before a court of law the party impugned cannot be judge in his own cause. Thus, the shopwalker who takes the protesting woman customer into the manager's office as a suspected thief cannot, when he or the store is sued for false imprisonment, simply say as a sufficient answer that he thought he had reasonable cause. On that issue the judge must decide. ”

“ It has always been one of the pillars of freedom, one of the principles of liberty for which on recent authority we are now fighting, that the judges are no respecters of persons and stand between the subject and any attempted encroachments on his liberty by the executive, alert to see that any coercive action is justified in law. ”

“ To require that a cause of belief shall be reasonable necessarily implies a reference to some standard of reasonableness. Is the standard of reasonableness which must be satisfied an impersonal standard independent of the Secretary of State's own mind, or is it the personal standard of what the Secretary of State himself deems reasonable? ”

“ I can imagine the counsel for the plaintiff insisting that the case should be fully tried, that he was entitled to cross-examine the Secretary on a matter personal to himself, that part evidence might be edited and selected, that the judge could not decide the case unless he had all the evidence, and that the defendant (on whom the appellants allege rests the burden of justifying the detention) must fail in his defence if he refuses to disclose material evidence, even on the ground that to disclose it is against the national interest. ”

“ But I remind myself, in Lord Atkinson's words, that “however precious the personal liberty of the subject may be there is something for which it may well be, to some extent, sacrificed by legal enactment, namely, national success in the war or escape from national plunder or enslavement”: Rex v. Halliday [1917] AC 260, 271 . The liberty which we so justly extol is itself the gift of the law and as Magna Carta recognizes may by the law be forfeited or abridged. ”

“ He has to bear in mind that the constable's authority is limited and that he can only arrest on reasonable suspicion, and the judge has the duty to say whether the conditions of the power are fulfilled. If there are reasonable grounds, the judge has no further duty of deciding whether he would have formed the same belief any more than, if there is reasonable evidence to go to a jury, the judge is concerned with whether he would have come to the same verdict. For instance, the minister may have reasonable grounds on the information before him for believing that a person is of “hostile origin.” ”

“ A very familiar use of the words is in actions for malicious prosecution where the plaintiff has to establish the absence of reasonable or probable cause in the prosecutor for instituting the prosecution. The relevant facts known to the prosecutor are, if necessary, determined by the jury. The judge determines whether they constitute reasonable cause. The inquiry is “objective,” and the cause of action, if established with the essential element of malice, exists against any person, rich or poor, powerful or weak, including any member of the executive, whether Secretary of State or not. ”

“ In some cases the issue is one of fact, in others of both fact and law, but in all cases the words indicate an existing something the having of which can be ascertained. And the words do not mean and cannot mean “if A thinks that he has.” “If A has a broken ankle” does not mean and cannot mean “if A thinks that he has a broken ankle.” “If A has a right of way” does not mean and cannot mean “if A thinks that he has a right of way.” “Reasonable cause” for an action or a belief is just as much a positive fact capable of determination by a third party as is a broken ankle or a legal right. ”

“ My Lords, I think we should approach the construction of reg. 18B of the Defence (General) Regulations without any general presumption as to its meaning except the universal presumption, applicable to Orders in Council and other like instruments, that, if there is a reasonable doubt as to the meaning of the words used, we should prefer a construction which will carry into effect the plain intention of those responsible for the Order in Council rather than one which will defeat that intention. ”

“ If, he says, persons having a limited authority “do any act beyond the limit of their authority, they thereby subject themselves to an action of trespass: but if the act done be within the limit of their authority, although it may be done through an erroneous or mistaken judgment, they are not thereby liable to such action.” The respondents rely on the order for the detention of the appellant above referred to. If it is valid, the action must clearly fail. The appellant, accordingly, seeks to throw on the respondents the burden of justifying the order. ”

“ The appellant's right to particulars, however, is based on a much broader ground, a principle which again is one of the pillars of liberty in that in English law every imprisonment is prima facie unlawful and that it is for a person directing imprisonment to justify his act. The only exception is in respect of imprisonment ordered by a judge, who from the nature of his office cannot be sued, and the validity of whose judicial decisions cannot in such proceedings as the present be questioned. ”