In a matter regarding unlawful surveillance the Constitutional Court held that the proper functioning of our legal system is reliant on the confidentiality of communications between lawyer and client. That promotes the rule of law.
Although originally sourced from the common law, legal professional privilege is now supported by the Constitution. The court reaffirmed a previous decision that legal professional privilege is an essential part of the rights to a fair trial and fair hearing. Communications between attorney and client must be protected to facilitate the proper functioning of an adversarial system of justice because it encourages full and frank disclosure between advisors and clients. In criminal proceedings the right to have privileged communications with the lawyer protected upholds the right to a fair trial in section 35 of the Constitution and has to be taken very seriously indeed.
The court found that the wholesale interception of lawyer/client communications without any recognition of this legal and constitutional reality would be at odds with the rule of law. The Regulation of Interception of Communications and Provision of Communication-Related Information Act, 2002 (RICA) is thus unconstitutional to the extent that, when the intended subject of surveillance is a practising lawyer, it fails to provide for additional safeguards calculated to minimise the risk of infringing the confidentiality of practising lawyer and client communications.
The court did not suggest that practising lawyers should not be subject to surveillance including interception of their communications. Lawyers are not immune from surveillance that is justified if there are reasonable grounds for suspecting them of being guilty of serious criminality or conduct that places the security of the Republic at serious risk.
[AmaBhungane Centre for Investigative Journalism v Minister of Justice  ZA CC 3]