## Facts

- The case involved Privacy International challenging the decisions of the Investigatory Powers Tribunal (IPT), a specialist body responsible for hearing complaints against intelligence agencies.
- Section 67(8) of the Regulation of Investigatory Powers Act 2000 (RIPA) included an ouster clause stating that “determinations, awards and other decisions of the Tribunal (including decisions as to whether they have jurisdiction) shall not be subject to appeal or be liable to be questioned in any court.”
- Privacy International argued that the ouster clause in RIPA unlawfully sought to exclude the courts' supervisory jurisdiction over the IPT, especially in cases of alleged errors of law.
- The core issue before the Supreme Court concerned whether such an ouster clause effectively prevented judicial review of the IPT’s decisions, and whether Parliament could lawfully exclude judicial oversight in this context.

## Issues

1. Whether section 67(8) of RIPA lawfully excluded judicial review of IPT decisions, including those based on an error of law.
2. Whether Parliament possesses the constitutional authority to entirely oust the High Court’s supervisory jurisdiction through legislative provision.
3. To what extent the principle of legality limits Parliament’s ability to curtail judicial review and exclude court oversight of public body decisions.

## Decision

- The Supreme Court held that section 67(8) of RIPA did not exclude the High Court’s supervisory jurisdiction where an error of law is alleged.
- The majority, led by Lord Carnwath, reasoned that determinations tainted by any error of law are nullities and thus fall outside the protection of the ouster clause.
- The Court held that ambiguous statutory language is insufficient to remove judicial review; Parliamentary intention to exclude court review must be expressed with absolute clarity.
- Lord Sumption dissented, arguing that the IPT’s judicial character sufficed for rule of law safeguards and that further judicial review was unnecessary; he contended that a right of appeal from a tribunal is not constitutionally required.
- The ruling clarified that judicial oversight of tribunals, even those with specialist knowledge, cannot be entirely ousted by legislation where errors of law are alleged.

## Legal Principles

- Judicial review serves as a core mechanism for ensuring public bodies act within the law and respecting the rule of law.
- Ouster clauses must be drafted in explicit and unequivocal terms to even attempt to restrict judicial review, and such attempts remain subject to limits imposed by the principle of legality.
- The principle of legality means Parliament must use “the greatest precision” if it intends to curtail court oversight and cannot be presumed to do so by implication.
- The separation of powers demands that courts determine the limits of their review in accordance with the rule of law, not at the sole discretion of Parliament.
- The judiciary retains the constitutional responsibility to interpret the scope and effectiveness of statutory attempts to restrict judicial review.

## Conclusion

The Supreme Court in R (Privacy International) v Investigatory Powers Tribunal [2019] UKSC 22 affirmed that ouster clauses cannot effectively exclude judicial review for errors of law, strengthening the constitutional requirement that the courts retain supervisory jurisdiction over the actions of public bodies and upholding the principle of legality against legislative attempts to limit judicial oversight.