The question arose in the context of the privilege against self-incrimination. Unlike the United States which safeguards this privilege by the Fifth Amendment of its Constitution, it subsists at common law (see Blunt v Park Lane Hotel Ltd  2 KB 253) and is reinforced by s.14 of the Civil Evidence Act 1968. But there are loads of exceptions to this rule as the Master of the Rolls noted at paragraph  of his judgment in Coogan:
"section 31 of the Theft Act 1981 and section 13 of the Fraud Act 2006 each remove the right to claim PSI in connection with offences under the Act in which they are respectively contained; section 98 of the Children Act 1989 removes the right in relation to evidence on applications relating to the care, supervision or protection of a child; sections 43A and 44 of the Insurance Companies Act 1982, section 433 of the Insolvency Act 1986 and section 434 of the Companies Act 1985 (as amended in each case by section 59 of, and schedule 3 to, the Youth Justice and Criminal Evidence Act 1999) remove PSI in relation to certain statutory company investigations; and section 2 of the Criminal Justice Act 1987 and para 5 of schedule 6 to the Terrorism Act 2000 also remove the right in certain circumstances."
And s.72 (1) and (2) of the Senior Courts Act 1981 provide yet another.
The reason for s.72 of the 1981 Act is that search orders (which used to be called Anton Piller orders and in many countries still are) and freezing injunctions usually require respondents to provide information on oath. For instance, paragraphs 18 and 19 of the model search order in the Annex to Practice Direction 25A - Interim Injunction provides:
"18. The Respondent must immediately inform the Applicant’s Solicitors (in the presence of the Supervising Solicitor) so far as he is aware –
(a) where all the listed items are;
(b) the name and address of everyone who has supplied him, or offered to supply him, with listed items;
(c) the name and address of everyone to whom he has supplied, or offered to supply, listed items; and
(d) full details of the dates and quantities of every such supply and offer.
19.Within [ ] working days after being served with this order the Respondent must swear and serve an affidavit setting out the above information."
Similarly, paragraphs 9 and 10 of the model freezing injunction in the same Annex require:
9. (1) Unless paragraph (2) applies, the Respondent must [immediately] [within hours of service of this order] and to the best of his ability inform the applicant’s solicitors of all his assets [in England and Wales] [worldwide] [exceeding £ in value] whether in his own name or not and whether solely or jointly owned, giving the value, location and details of all such assets.
(2) If the provision of any of this information is likely to incriminate the respondent, he may be entitled to refuse to provide it, but is recommended to take legal advice before refusing to provide the information. Wrongful refusal to provide the information is contempt of court and may render the Respondent liable to be imprisoned, fined or have his assets seized.
10. Within [ ] working days after being served with this order, the Respondent must swear and serve on the Applicant’s solicitors an affidavit setting out the above information.
It will be noted that there are slight differences between the wording of the corresponding provisions of the search order and freezing injunction and that is because s.72 nearly always applies in cases where a search order is sought but not necessarily where there is a freezing injunction.
The provisions of s.72 that the Court of Appeal considered were as follows:
"(1) In any proceedings to which this subsection applies a person shall not be excused, by reason that to do so would tend to expose that person … to proceedings for a related offence … :
(a) from answering any question put to that person in the first-mentioned proceedings; or
(b) from complying with any order made in those proceedings.
(2) Subsection (1) applies to the following civil proceedings in the High Court, namely:
(a) proceedings for infringement of rights pertaining to any intellectual property or for passing off;
(b) proceedings brought to obtain disclosure of information relating to any infringement of such rights or to any passing off;
(c) proceedings brought to prevent any apprehended infringement of such rights or any apprehended passing off.
(3) …. [N]o statement or admission made by a person:
(a) in answering a question put to him in any proceedings to which subsection (1) applies; or
(b) in complying with any order made in any such proceedings,
shall, in proceedings for any related offence ... , be admissible in evidence against that person …........................................
(5) In this section:
"intellectual property" means any patent, trade mark, copyright, design right, registered design, technical or commercial information or other intellectual property;
"related offence", in relation to any proceedings to which subsection (1) applies, means:
(a) in the case of proceedings within subsection (2)(a) or (b):
(i) any offence committed by or in the course of the infringement or passing off to which those proceedings relate; or
(ii) any offence not within sub-paragraph (i) committed in connection with that infringement or passing off, being an offence involving fraud or dishonesty;
(b) in the case of proceedings within subsection (2)(c), any offence revealed by the facts on which the plaintiff relies in those proceedings."
In separate proceedings brought by the comedian Stephen Coogan (Gray v News Group Newspapers Ltd & Another  EWHC 349 (Ch),  2 All ER 725,  2 WLR 1401) and Max Clifford's personal assistant (Phillips v Newsgroup Newspapers Ltd and Others  EWHC 2952 (Ch) (17 Nov 2010) against News Group Newspapers for phone hacking, the claimants sought orders requiring the private investigator Glenn Mulcaire to state on oath who had ordered the interception of their mobile messages. In each case, Mr. Mulcaire raised the privilege against self-incrimination. In each case that plea was answered by the argument that this was an intellectual property claim to which the privilege against incrimination did not apply. In both cases, the judge below agreed with the claimants. News Group and Mr. Mulcaire appealed both decisions.
The points raised in both appeals were that:
"i) Information obtained by Mr Mulcaire from intercepting the voice messages of Ms Phillips and/or Mr Coogan was not 'intellectual property' and therefore section 72 cannot apply;
ii) If the information in question was 'intellectual property':
(a) Mr Mulcaire would, if he were required to provide all the information ordered by Mann J, and some of the information ordered by Vos J, be at risk of being prosecuted for an offence which is not a 'related offence', so section 72 does not apply;
(b) Section 72 is inconsistent with Article 6 of the European Convention on Human Rights ('the Convention'), and the court should accordingly make a declaration of incompatibility."
A very strong Court of Appeal (Lord Judge LCJ, Lord Neuberger MR and the Vice-President of the Court of Appesl) decided against Newsgroup and Mr. Mulcaire on both grounds.
As to the first point, their lordships noted that S.72 (5) already included "technical or commercial information" within the definition of intellectual property. The question was whether personal information could be so defined. The Court agreed with the defendant that information (confidential or otherwise) was not property and in many instances not particularly intellectual but it fell nevertheless within the ambit of the words "or other intellectual property". As the Master of the Rolls explained:
"49.......It seems to me clear that, under the law as it had been developed well before the 1998 Act came into force, personal information which was of sufficient significance to attract the notice of the courts, which had been, for instance, left on a person's telephone answering machine, and was clearly intended to be confidential as between the caller and that person, would have attracted protection under the law of confidential information. While 'trivial tittle tattle' (Coco v Clarke  RPC 41, 48) would not, information of a personal private information would in principle have been protected by the law of confidence (at least if it was not in public knowledge) – see the cases referred to in para 48 above, a view supported by the reasoning and conclusion in Francome v Mirror Group Newspapers Ltd  1 WLR 892.
50. Further, following Lord Goff's authoritative observations in Attorney-General v Guardian Newspapers Ltd (No 2)  1 AC 109, 281, it is clear that, if information had come into a person's hands by happenstance, and that person should have appreciated that it was confidential, he will be bound by the confidence. A fortiori where the person intentionally obtains the information knowing that he was not intended to receive it, and even more so where he uses unlawful means to obtain it – see again Francome  1 WLR 892. While it may nonetheless have been arguable (if, in the view of many people, illogical) that, prior to the 1998 Act coming into force, that principle would not have applied to personal confidential information (in the light of Kaye  FSR 62), such an argument is no longer maintainable in the light of Article 8 and Campbell v MGN Ltd  UKHL 22,  2 AC 457.
51. There are also practical reasons why 'intellectual property' in section 72(5) should include personal confidential information if it also includes commercial confidential information. It would be surprising if PSI could be invoked by a defendant in relation to a breach of confidence claim which related to personal information, but not where the nature and circumstances of the claim were identical, save that it related to commercial information. Although the statutory provisions which remove PSI appear somewhat piecemeal, that is no reason for concluding that a particular provision should be interpreted so as to lead to an arbitrary result.
52. Further, the same information could be commercial in one person's hands and personal in the hands of another. A good example may be found in Douglas  QB 125, where wedding photographs were held to be the subject of a personal confidential claim by the happy couple, but of a commercial confidential claim by the magazine to whom they had sold the exclusive publication rights – and see in the House of Lords per Lord Hoffmann at  1 AC 1, para 118. Equally, as Cornish (op cit) points out at para 8-39, 'some people want privacy largely so that they can turn it to their own financial advantage'. If commercial information, but not personal, information is within section 72, then the applicability of the section could, in some cases, turn on how the claim is pleaded – a most unattractive result."
The Court of Appeal also rejected the second argument that the exception to the privilege against self-incrimination has to be interpreted very narrowly so that it would not apply to a case where the respondent is at risk of being prosecuted for an offence that extends beyond the breach of confidence or other intellectual property infringement.
Finally, there was nothing in the European Convention of Human Rights that precluded restrictions on the privilege against self-incrimination per se as the Court of Human Rights had ruled in cases on the point.