The important general principle is of course that a party to whom a document has been disclosed in litigation may use that document only for the purpose of the proceedings in which it is disclosed. There are, nonetheless, three significant exceptions to that principle, set out in CPR r31.22(1). They are (a) where the document has been read to or by the Court, or referred to, at a hearing which has been held in public; (b) where the Court gives permission; or (c) where the party who disclosed the document and the party to whom the document belongs agree. However, r31.22(2) provides that the Court may make an Order restricting or prohibiting the use of a document which has been disclosed, even where the document has been read to or by the Court, or referred to, at a hearing which has been held in public. An application for such an Order was considered by the High Court in Smith & Nephew PLC v Convatec Technologies Inc  EWHC 146 (Pat). Birss J granted a Permanent Order prohibiting the use after trial of certain documents which had been disclosed during patent infringement proceedings. The documents covered by the Order included those which made reference to commercial strategy or to manufacturing processes. The nature and details of the claimants’ secret processes had to be explored in the proceedings. Justice could not be done without it. A number of those documents played a crucial role in Court, but the outcome could be understood without them. The documents covered by the Order did not, however, include documents which related to the claimants’ dealings with regulatory authorities, which went to a springboard injunction question. Although the claimants had built up very substantial experience and know-how in dealing with regulatory authorities, disclosure of those documents would not reveal that know-how or damage the claimants at all.
An Order restricting use of disclosed documents referred to in Court is consistent with it being “highly desirable” (para 11) to avoid trials in private or partly in private, as was recently reiterated by Lord Neuberger in Bank Mellat v H. M. Treasury  UKSC 38 at para 2.