By Alison L Young
Sir David Williams Professor of Public Law, University of Cambridge
In R (Privacy International) v Investigatory Powers Tribunal  UKSC 22 the Supreme Court was asked to interpret an ouster clause. Ouster clauses remove the ability of the court to review decisions of the executive. This clause said that decisions of the Investigatory Powers Tribunal (IPT) could not be questioned in a court. The clause specifically excluded decisions taken by the IPT as to the scope of its powers – a ‘jurisdictional’ decision.
The case split the Supreme Court. The majority (4) concluded that the wording of the legislation was not clear enough to remove the ability of the courts to review decisions of the IPT if they made a legal error. It only removed the ability of the courts to review decisions of the IPT which made a jurisdictional error when this was an error about the facts. The minority (2) concluded that the ouster clause was clear enough to remove the ability of the courts to review decisions of the IPT that may a legal error.
But only substantive legal errors – if the IPT made a legal error when determining the law that applied to the case being heard by the IPT. It did not exclude the ability of the courts to review a decision of the IPT if they made an error as to their procedures – e.g. if the IPT was meant to sit as a tribunal of 3, but only 2 members of the IPT had heard a case. A further minority judgment (1) concluded that the clause did remove the ability of the court to review decisions for the IPT when it made a legal error.
There is also obiter dicta in the decision. This is a statement that is made in a decision which is not part of the reasoning of the court. It does not form a precedent. This means that other courts do not have to follow this dicta. Lord Carnwath’s obiter dictum applied to ouster clauses that removed the ability of the court to review an administrative body that had been given limited powers in legislation. He said that courts would not enforce a clause that would remove judicial review when that body made a mistake as to the scope of its powers, or made a legal error. Lord Wilson’s obiter dictum appeared to give support for Lord Carnwath’s statement, but only so far as this applied to the court reviewing a decision of an administrative body that made a mistake as to the scope of its powers.
Critics of the case think the court went too far, contradicting the will of Parliament. Parliament had clearly set out in legislation that the courts were not to review decisions of the IPT. Those who support the case argue that courts should look at legislation carefully when it restricts the ability of courts to review decisions of administrative bodies. Very clear words are needed to ensure that Parliament really did want to restrict judicial review.
Critics also argue that the obiter dicta of the courts went too far, undermining parliamentary sovereignty and challenging democracy. Supporters argue that the obiter dicta is necessary to protect the rule of law. If Parliaments creates an administrative body with limited powers, then courts have to be able to police those limits, otherwise that administrative body no longer has limited powers. Judicial review is needed to ensure all administrative bodies act within the scope of the law and courts should ensure they protect this to maintain a good constitutional balance.