Providing documents to a solicitor for the purpose of obtaining advice about privilege claims is itself a privileged communication, even where that solicitor also acts for another party, and the onus of proving waiver lies on the party asserting it.
The full text is available to signed-in members, including the 4 later cases that cite this judgment.
1 of the 4 citing cases carry a classified treatment. How each court treated it is available to signed-in members.