21 In the same case Wilson and Dawson JJ found
It is beyond question that at common law no person has power to arrest a person merely for the purpose of questioning him: Beckwith v. Philby (1827) 6 B & C 635; 108 ER 585; Mathews v. Biddulph (1841) 3 Man & G 390; 133 ER 1195; Hadley v. Perks (1866) 1 QB 444; Nolan v. Clifford [1904] HCA 15; (1904) 1 CLR 429; Walters v. W.H. Smith & Son, Limited (1914) 1 KB 595; Christie v. Leachinsky [1947] UKHL 2; (1947) AC 573. The question in this case is whether a policeman has any power to defer bringing before a justice a person whom he has arrested in order to use the time to question the person or to investigate in some other way the offence or offences upon suspicion of which the arrest was made or any other offence or offences which the arrested person may have committed. Apart from the decision in Dallison v. Caffery (1965) 1 QB 348, to which we shall refer in a moment, we should have thought that the answer to that question was clear. A person who is arrested may be detained only for the purpose of bringing him before a justice (or nowadays before some other person with power to deal with him) to be dealt with according to law. For arrest is the beginning of imprisonment and, whilst it is recognized that imprisonment before trial may be necessary in the administration of criminal justice, it must be justified in accordance with the law. There must be a charge and if the person charged can establish his entitlement to bail and can furnish it, the law requires that he be released subject to any conditions which might be imposed upon him. The function of the justice in granting or withholding bail is an ancient one: 1, 2 Philip and Mary c.13; Holdsworth's History of English Law , 5th ed. (1931), vol.I, p.296. The point at which an arrested person is brought before a justice upon a charge is the point at which the machinery of the law leading to trial is put into operation. It is the point from which the judicial process commences and purely ministerial functions cease.
9. This being the purpose of arrest, any delay in bringing a person under arrest before a justice, even if it is to effectuate some other purpose such as the questioning of that person in order to dispel or confirm the suspicion which was the basis of the arrest, is to defeat, however temporarily, the true purpose. Where no delay is involved, there can, of course, be no objection to the occasion of the arrest and subsequent detention being used for the purpose of further investigation of the offence in question or, for that matter, any other offences, provided the investigation is properly carried out and any necessary caution is given: see Hough v. Ah Sam [1912] HCA 78; (1912) 15 CLR 452. But to conduct an investigation which does not cut across the purpose for which a person is held under arrest is one thing; to disregard that purpose in order to carry out an investigation is another thing, however much the further investigation may be otherwise necessary or desirable. A person is not to be imprisoned otherwise than upon the authority of a justice or a court except to the extent reasonably necessary to bring him before the justice to be dealt with according to law. That, as we conceive it, is one of the foundations of the common law.
10. It is by writ of habeas corpus that the immediate restoration to freedom of a person illegally detained may be achieved. That is a remedy as old as the law and was declared by the Bill of Rights 1688 to be so. We know of no authority whereby the writ may be refused upon the basis that a person, having been arrested, is required for further questioning. The imprisonment of a person can be justified only by lawful warrant or in the limited circumstances where he is held under lawful arrest for the purpose of obtaining the warrant of a justice for any further detention.
11. Because the extent of the power of arrest and the deprivation of freedom which it involves are such important matters, it is not surprising that the law has been expressed in an uncompromising way. In Bales v. Parmeter (1935) 35 SR (NSW) 182, in a passage which has frequently been cited with approval in this country, Jordan C.J. put it as follows at pp.188-189:
"But suspicion that a person has committed a crime cannot justify an arrest except for a purpose which that suspicion justifies; and arrest and
imprisonment cannot be justified merely for the purpose of asking questions ... No person is entitled to impose any physical restraint upon another except as authorised by law. This rule applies as much to police officers as to any one else, although the law allows them somewhat greater powers in this respect than it allows to other citizens. Where the imposition of physical restraint is authorised by law it may be imposed
only for the purpose for which it is authorised ...it may be imposed by a police officer in the course of arresting and bringing before a magistrate a
person for whose arrest no warrant has issued, but whom the officer, with reasonable cause, suspects of having committed a crime or an offence punishable whether by indictment or summarily under any Act. This authority existed with respect to felonies at common law. It was extended to other offences by statute - now s.352(2)(a) of the Crimes Act 1900. But the statute, like the common law, authorises him only to take the person so arrested before a justice to be dealt with according to law, and to do so without unreasonable delay and by the most reasonably direct route: Clarke v. Bailey (33 SR 303). Any detention which is reasonably necessary until a magistrate can be obtained is, of course, lawful, but detention which extends beyond this cannot be justified under the common law or statutory power. Thus, it has been held that if in the course of an arrest which is otherwise for a lawful purpose, the arresting constable takes the arrested person to some place to which it would not
be reasonable and proper to take him in the course of bringing him before a magistrate, for the purpose of searching him there, the detention in
that place and the search are unauthorised and therefore actionable: ibid."