In Lok Momin v Hospital Authority  2 HKLRD 152, the Hong Kong Court of First Instance held that the doctrine of partial waiver of privilege cannot apply to privileged documents disclosed at the trial of a preliminary issue so as to preserve privilege over those documents at the subsequent main trial.
The question of privilege arose at a trial of a preliminary issue of limitations in a personal injury action, the main trial of which would take place if the Court were to displace the limitation period.
At the preliminary issue trial, the plaintiff sought to invoke the doctrine of partial waiver of privilege in respect of privileged documents adduced as evidence, with the aim that those documents would remain privileged for the purposes of (and not be deployed at) the main trial.
The doctrine of partial waiver of privilege allows parties to waive privilege in documents so that they can be disclosed for a limited purpose only (for example, disclosure to a regulator for the purposes of an investigation). This will not waive privilege for all purposes or to all third parties. The Court acknowledged the cases affirming this doctrine. However, the Court’s view was that partial waiver in those cases occurred in the context of different investigations and different proceedings. Notably, the Court distinguished those instances from the circumstances in this case which concerned a trial of a preliminary issue before proceeding to the main trial.
The Court stated that there is no direct authority addressing the question of whether the deployment of privileged documents at the trial on the preliminary issue of limitations will result in the privilege over those documents being waived at the main trial (that would take place if the court disapplies the limitation period).
The Court went on to consider the view adopted by the editor of Thanki’s The Law of Privilege (Third Edition, 2019), which states that a party deploying otherwise privileged documents in an interlocutory proceeding will generally be held to have waived the privilege for the use at trial, as it will be impossible for most practical purposes to ‘turn the clock back’ when privileged material has already been relied on by a party during the interlocutory stage.
The Court also found a similar view expressed by Gloster J in the case of Berezovsky v Abramovich  EWHC 1143 (Comm) (although on the facts of that case, the court held that the claimant was entitled to assert privilege in a draft witness statement relating to separate litigation, despite having previously copied the draft to the defendant in the proceedings of the case in question). Gloster J held that in situations where there has been an extensive deployment in interlocutory proceedings of privileged material in order to support a party’s case on the substantive merits of his/her claim or defence, such deployment engages the collateral waiver principle, and it is then too late for the deploying party to attempt to turn the clock back, even if he/she had not made up his/her mind whether to refer to such evidence at trial.
Taking a close look at the context of this case, the Court envisaged that in practice courts do not always order a trial of a preliminary issue as to limitations in every case where a limitations defence is pleaded. Instead, there may well be cases where courts simply direct that all issues of limitations, liability and quantum be tried together. As a result, it will be discriminatory if a party to a trial of a preliminary issue enjoys the right to invoke the doctrine of partial waiver of privilege but a party to a trial where all issues of limitations, liability and quantum are tried together does not enjoy the same right.
In conclusion, the Court held that the deployment of privileged documents at a trial of a preliminary issue will mean that the privilege over those documents is also waived for the purposes of the subsequent main trial.
This case clarifies the law in respect of whether privilege may be claimed, through the doctrine of partial waiver of privilege, at a subsequent main trial over privileged documents that were deployed at the trial on a preliminary issue. With no previous case authority in Hong Kong on point, the Court welcomed the opportunity to clarify this area of law and the ruling will now serve as a precedent for future similar cases. The findings in this case should serve as a warning to practitioners and their clients of the risks of seeking to make use of privileged documents in similar situations.