MADLANGA J [133] With this in mind, it is significant that in RICA there is an express prohibition of communication interceptions without interception directions. To interpret section 2(1)(a) of the NSIA in the manner suggested by the Minister of State Security would be to undermine this prohibition. Also, there is the principle of interpretation that says that where a provision is ambiguous, its meaning may be determined in light of other statutes on the same subject matter.164 This principle points away from the interpretation advocated by the Minister, particularly because it results in an intrusion into the privacy right that is expansive in its reach and most egregious in nature. [134] Also, the section has shortcomings of another nature and these too impact negatively on the privacy right. This as well is an indication that the section ought not to be interpreted to authorise bulk surveillance. The section does not stipulate in clear, precise terms the manner, circumstances or duration of the collection, gathering, evaluation and analysis of domestic and foreign intelligence. It merely broadly enumerates the “functions” of the State Security Agency, with no details as to the nuts and bolts of those functions. It also fails to set out the ambit of how these various types of intelligence must be captured, copied, stored, or distributed. It is thus not clear at all that section 2 provides for a practice that so significantly intrudes on the right to privacy. [135] In sum, I am not convinced that the broad terms of section 2 serve as authorisation for the practice of bulk surveillance. The practice is thus unlawful and invalid, as there is no law that authorises it. Remedy [136] Questions that arise from what was argued are whether – in the exercise of this Court’s remedial power under section 172(1)(b) – we should: limit the retrospective effect of the declaration of invalidity; suspend the declaration and, if so, for how long; 164 Independent Institute of Education (Pty) Ltd v Kwazulu-Natal Law Society [2019] ZACC 47; 2020 (2) SA 325 (CC); 2020 (4) BCLR 495 (CC) at para 38. 71