In common law jurisdictions and some civil law jurisdictions, legal professional privilege protects all communications between a professional legal adviser (a solicitor, barrister or attorney) and his or her clients from being disclosed without the permission of the client.
The earliest recorded instance of the principle in English case-law dates from 1577 in the case of Berd v. Lovelace[2] the full report of which states: Thomas Hawtry, gentleman, was served with a subpoena to testify his knowledge touching the cause in variance; and made oath that he hath been, and yet is a solicitor in this suit, and hath received several fees of the defendant; which being informed to the Master of the Rolls, it is ordered that the said Thomas Hawtry shall not be compelled to be deposed, touching the same; and that he shall be in no danger of any contempt, touching the not executing of the same process.The principle originated as protection for individuals when accessing the knowledge and legal resources available to a lawyer and was said to stem from the "oath and honour" of the lawyer, a sort of special contractual relationship.
It was based on the fact that the ordinary citizen could not safely navigate the complexities of the law and justice system without some assistance.
However, without protection the quality of the advice would suffer as clients would be discouraged from making full disclosure to their legal representatives.
It is not (as has sometimes been said) on account of any particular importance which the law attributes to the business of legal professors, or any particular disposition to afford them protection ...
If the privilege did not exist at all, every one would be thrown upon his own legal resources, deprived of professional assistance, a man would not venture to consult any skilful person, or would only dare tell his counsellor half his case".
The rules of court in NSW extends the definitions in the Evidence Act to discovery and inspection of documents.
[7] Solicitor–client privilege was initially a common law evidentiary principle similar to hearsay but has since become recognized as a substantive rule that is constitutionally protected.
445, the Court found that solicitor–client privilege was a principle of fundamental justice, hinting that it may be protected under Section 7 of the Charter.
In addition, the United States Supreme Court has ruled that the privilege generally does not terminate upon the client's death.