I may end with two more recent affirmations of the general principle. In Hobbs v Hobbs and Cousens  P.112, 116-117 Stevenson J. said: "privilege has a sound basis in common sense. It exists for the purpose of ensuring that there shall be complete and unqualified confidence in the mind of a client when he goes to his solicitor, or when he goes to his counsel, that that which he there divulges will never be disclosed to anybody else. It is only if the client feels safe in making a clean breast of his troubles to his advisers that litigation and the business of the law can be carried on satisfactorily . . . There is ... an abundance of authority in support of the proposition that once legal professional privilege attaches to a document . . . that privilege attaches for all time and in all circumstances."
In Balabel v. Air India  Ch. 317 the basic principle justifying legal professional privilege was again said to be that a client should be able to obtain legal advice in confidence.
The principle which runs through all these cases, and the many other cases which were cited, is that a man must be able to consult his lawyer in confidence, since otherwise he might hold back half the truth. The client must be sure that what he tells his lawyer in confidence will never be revealed without his consent. Legal professional privilege is thus much more than an ordinary rule of evidence, limited in its application to the facts of a particular case. It is a fundamental condition on which the administration of justice as a whole rests.