Whether witness owes duty of confidentiality to a party before trial

The defendants applied for an order allowing them to interview a prospective witness about certain topics. That witness was an employee of the claimant. It is the accepted position that a party can call any witness (including the employee or ex-employees of the other side) to give evidence at trial and that witness is obliged to answer questions puts to him or her. In doing so, the witness will not be in breach of his/her duty of confidentiality owed to his/her employer. It was equally accepted that the witness cannot reveal matters which are confidential before trial (on the basis that those answers would be relevant and admissible at trial). However, of issue in this case was whether the claimant had waived confidentiality in certain specific matters by pleading them.

The defendant sought to rely on prior caselaw concerning the waiver of privilege to draw an analogy with waiver of confidentiality.

Privilege can be waived expressly (which includes waiver by pleading), impliedly (where eg a party sues its solicitor, thus waiving the right to rely on legal professional privilege because the court is being asked to rule on issues arising from the client/solicitor relationship), or by collateral waiver (ie waiver of other privileged material that is part of the same "transaction").

In this case, the defendant claimed that there had been an express waiver because of the way the claimant had pleaded its case. The judge considered whether "If a claimant, in a case in which he is suing not his former solicitor but a third party, pleads a privileged document, does this amount to an express waiver of privilege in that document?" He answered this question ""Yes". Or, to be more precise, it amounts to an announced intention to rely on, and hence waive privilege in, the document at trial, and thus … he is put to an election either to abandon his reliance on the document, or to accept that privilege has been waived".

But did the same principles apply to waiver of confidentiality in a non-privileged document? The judge held that they did not. Confidential documents must be disclosed in the course of litigation if they are relevant to the pleaded issues. Where privilege is waived, all privileged documents relevant to the issue will have to be disclosed. But the same is not true for waiver of confidentiality: "though such confidential matters have been referred to in disclosed documents and thereby have come into the possession of the other party, that does not entail the further consequence that a potential witness who owes a duty of confidentiality to the disclosing party is now free to talk about such matters to anybody he wishes to" before trial.

Accordingly, the court had no discretion to allow the defendants to interview the witness before trial and the application was dismissed.