Liberty, R (On the Application Of) v The Prime Minister & Anor

An appellate court should interfere with a case-management decision only where the decision falls outside the generous ambit of discretion because of a material error of principle or plain wrongness.

Parties should not pursue substantially identical public law issues in parallel proceedings in different UK jurisdictions. Parallel litigation risks conflicting decisions, inconsistent discretionary orders and wasted judicial resources, and is inconsistent with judicial comity. An urgent hearing may therefore be refused where another competent UK court is already seised of, or has decided, the same issues. The substantive scope of the frustration principle under the European Union (Withdrawal) (No. 2) Act 2019 was not determined.

Liberty sought permission to appeal from a case-management decision of Supperstone J in the Administrative Court, which refused an urgent hearing of its judicial review claim against the Prime Minister. The claim alleged that his conduct might breach the statutory obligations in sections 1(3) and 1(4) of the European Union (Withdrawal) (No. 2) Act 2019, including the obligation to seek an extension under Article 50(3) of the Treaty on European Union.

Related Scottish proceedings raised the same arguments. The Outer House dismissed them in Vince and others v The Right Honourable Boris Johnson MP and Lord Keen of Elie QC [2019] CSOH 77, and the Inner House upheld that outcome in the same case [2019] CSIH 51, while reserving further consideration in light of intervening events. The central issue was whether the English proceedings should nevertheless be expedited so that their substance could be considered.

Permission to appeal was refused. The application concerned only Supperstone J’s case-management decision, not the substantive legality of the Prime Minister’s proposed conduct.

1. The ordinary route for reversing a paper case-management decision is an oral hearing below. Although the Court of Appeal had jurisdiction to entertain the application without such a hearing, that was an exceptional course justified only by extreme urgency.
2. The court applied the high hurdle described in BPP Holdings v HMRC [2017] 1 WLR 2945, endorsing the approach in Walbrook Trustees (Jersey) Limited v Fattal [2008] EWCA Civ 427. An appellate court should not interfere where the judge applied the correct principles, considered relevant matters and excluded irrelevant matters, unless the decision was plainly wrong and outside the generous ambit of discretion. Supperstone J had made no error of principle and had not exceeded that ambit.
3. The statutory obligation arose from the Prime Minister’s office and applied throughout the United Kingdom. Courts in England and Wales, Scotland and Northern Ireland could determine public law challenges seeking to enforce the European Union (Withdrawal) (No. 2) Act 2019. It was wrong in principle to litigate substantially identical public law issues in parallel jurisdictions. Such duplication risked conflicting decisions, inconsistent discretionary orders and inefficient use of judicial time.
4. Judicial comity required respect for the Scottish proceedings and decisions. The principle was illustrated by British Airways Board v Laker Airways [1984] QB 142. If the Scottish courts were said to be wrong, the appropriate route was an application for permission to appeal to the Supreme Court, not an expedited and abbreviated review in parallel English proceedings.
5. The Part 18 response did not materially alter the position. Although events had moved rapidly and the statutory letter and a side letter had been sent, the Scottish courts remained the appropriate forum for the issues. The Court of Appeal did not decide whether an honestly expressed view, coupled with an intention to influence the European Council, would frustrate the Act. Refusing an urgent hearing was within the generous ambit of Supperstone J’s discretion and, in the circumstances, it would have been inappropriate to do otherwise.

• Court of Appeal (Civil Division): On 18 October 2019 the court refused Liberty’s application for permission to appeal, holding that no error of principle or discretionary error had been shown. The judgment is [2019] EWCA Civ 1761.
• Queen’s Bench Division (Administrative Court): Supperstone J refused an urgent hearing of Liberty’s judicial review claim on 11 October 2019. No citation for that decision is stated in the judgment.