West London Pipeline and Storage Ltd v Total UK Ltd [2008] EWHC 1729 (Comm), [2008] All ER (D) 294
(i) The burden of proof is on the party claiming litigation privilege to establish it.
(ii) An assertion of privilege is not determinative.
(iii) The affidavit of documents is conclusive unless it is reasonably certain from: (a) the statements of the party making it that he has erroneously represented or has misconceived the character of the documents in respect of which privilege is claimed;
(b) the evidence of the person who directed the creation of the communications or documents over which privilege is claimed that the affidavit is incorrect; and
(c) the other evidence before the court that the affidavit is incorrect or incomplete on the material points.
(iv) Where the court is not satisfied on the basis of the affidavit and the other evidence before it that the right to withhold inspection is established, it may: (a) conclude that the evidence does not establish a legal right to withhold inspection and order inspection;
(b) order a further affidavit to deal with matters which the earlier affidavit does not cover or on which it is unsatisfactory;
(c) inspect the documents (inspection should be a solution of last resort and should not be undertaken unless there is credible evidence that those claiming privilege have either misunderstood their duty, or are not to be trusted with the decision making, or there is no reasonably practical alternative); or
(d) order crossexamination of a person who has sworn an affidavit (however, cross-examination may not be ordered in the case of an affidavit of documents. In cases where the issue is whether or not the documents exist, the existence of the documents is likely to be an issue at the trial and there is a particular risk of a court at an interlocutory stage impinging on that issue).