The above statement – a little controversial, maybe – is not difficult to sustain. It derives from a comparison of Mostyn J’s obiter comments in UL v BK (Freezing Orders: Safeguards: Standard Examples)  UKHC 1735 (Fam) http://www.bailii.org/ew/cases/EWHC/Fam/2013/1735.html and the law as explained by Ward LJ in the Court of Appeal in Lifely v Lifely  EWCA Civ 904: http://www.bailii.org/ew/cases/EWCA/Civ/2008/904.html. In UL Mostyn J set out what he called ‘Imerman principles’. These are no more that his arbitrarily asserted deductions from Imerman v Tchenguiz and ors  EWCA Civ 908: http://www.bailii.org/ew/cases/EWCA/Civ/2010/908.html.; and nothing, as a careful reading of Imerman shows, of what was said in that case.
Lifely concerned two sons (A and B) of a farmer who, during his lifetime and with him, had agreed distribution of milk quota shares. After the father’s death they failed to agree what they had agreed and went to the Chancery Division for an answer. The chancery judge agreed with B. A year or so later A happened to find a diary belonging to B. He looked in it and found notes by B which appeared to record the terms which he, A, had said were agreed. He showed the diary to his solicitors who read the diary notes, one assumes; for they advised him to appeal to the Court of Appeal. The court permitted the diary to be produced (Ladd v Marshall  1 WLR 1489), allowed the appeal out of time, set aside the order and remitted the case for hearing on terms that the diary (which they said should ‘probably’ have been disclosed – ie listed as a relevant document) would be in evidence before the court below.
In Vernon v Bosley (No 2)  QB 18 the defendant’s leading counsel (A) received form an undisclosed source and read confidential documents (medical reports) about Mr Vernon (B), which disclosed information which, said the Court of Appeal, should have been disclosed. It was relevant evidence which had become available between the High Court hearing and the appeal hearing. This is the common law, said Stuart Smith LJ. The principle is now confirmed by Civil Procedure Rules 1998 r 31.11. Rebekah Brookes’s house-keeper (A) unlawfully took documents belonging to Brookes, handed them to the police and recently appeared as a feted witness in the long-running criminal trial of various NoW journalists.
In each of these three cases the documents were private: ie they belonged to someone else who had not authorised their being read by A. To that extent all were obtained and read unlawfully and in breach of B’s rights under European Convention 1950 Art 8. As will be seen, however, the failure to disclose may be overridden. At  Ward LJ said: ‘I am prepared to accept… that there is at least a good arguable claim for misuse of private information which is protected by Article 8 of the ECHR [ie all A’s in the above examples were in the wrong]. However, the matter does not end there’.
He then explained how he conducted the Art 6 – Art 8 balancing exercise required of judges to decide issues of this type; and concluded, as he must if Art 6 rights are engaged, that these trump Art 8 (paras  to ).
In UL Mostyn J was confronted with a wife (A); but at an early stage of proceedings. A had obtained a Mareva injunction (a freezing order per Civil Procedure Act 1997 s 7: not a provision cited once by Mostyn J) on the basis of documents she had taken ‘illegitimately’ (as the judge held). On that basis he held that ‘the wife seriously breached her duty of candour in not mentioning that she had accessed the husband’s safe illegitimately’ para ). He refused to renew the injunction. He left her to a forthcoming hearing of a breach of confidence (tort) claim by B in the Queen’s Bench Division.
Of private documents he says, at para , that if A ‘does access’ them then she ‘… is not only in jeopardy of criminal penalties but also risks being civilly sued by the husband for breach of confidence and misuse of his private material.’ At (iii) he goes on:
If a wife supplies such documents to her solicitor then the solicitor must not read them but must immediately seek to obtain all of them from the wife and must return them, and all copies (both hard and soft), to the husband’s solicitor (if he has one). The husband’s solicitor, who owes a high duty to the court, will read them and disclose those of them that are both admissible and relevant to the wife’s claim, pursuant to the husband’s duty of full and frank disclosure. If before that exercise has taken place the husband’s solicitor is dis-instructed the solicitor must retain those documents pending a further order of the court (judge’s emphasis).
Had Mostyn J heard full argument from a person who was employed to encourage him reflect upon this assertion (eg retained by the Law Society) he might have concluded that what he says here must apply almost precisely to brother A, to Brookes’s housekeeper, and perhaps to Miss Bosley’s QC. If his rule, as above, is correct then many non-discloser’s will be immune from further investigation since the evidence of non- disclosure must not be looked at, even if it is sitting on A’s kitchen table two years after a final order (eg B has returned to collect post, which includes letters from a bank of which A has never heard, but which is still coming to the former matrimonial home).
Mostyn J, the scourge of non-disclosers, in cases of discovery of genuine non-disclosure, becomes the cheat’s friend. It gets worse. The suggestion that a solicitor may not look at evidence, however obtained, is – it might be said – to misunderstand rules as to legal professional privilege, whose object is to enable a client fully to ‘bare his breast’ (the language of the time) to a legal adviser (Anderson v Bank of British Columbia (1876) 2 ChD 644 at 649 per Sir George Jessel MR); and, in the face of repeated House of Lords and Supreme Court authority is to ignore it (starting in the late twentieth century with R v Derby Magistrates’ Court exp B  1 AC 487).
It is unlikely that Art 6, which protects and justifies legal professional privilege, would countenance Mostyn J’s obiter comments. It would protect any lawyer asked to advise here as it protected A’s lawyers in Lifely. We must be allowed to do our job without judicial interference. We are officers of Mostyn J’s court and deserve the courtesy, at least, of an opportunity to reply; if only in support of those who believe – as did Mostyn J, once – that non-disclosure is a canker in the life-blood of civil litigation.
The law must be, I would assert on Court of Appeal authority, that the illegality of taking or reading private documents (other than those covered by legal professional privilege which are totally out-of-bounds: and solicitors must be trusted to spot that) depends on the point at which a duty to produce arises (they must always be ‘disclosed’: Family Procedure Rules 2010 r 21.1(1)). Once the duty to disclose arises then, as Ward LJ says, the illegality is not the end of the matter. Privacy will generally yield to Art 6; and Art 6 says that a fair trial depends on the court receiving all relevant evidence save that covered by any immunity or applicable privilege.
If this assessment is right then practising lawyers should have the chance to reply to Mostyn J, on behalf of the wronged parties whose exposure of fraud, misrepresentation and lies are – perhaps unwittingly – condoned by the arbitrary ‘guidance’ provided by UL v BK.