Could the courts stop Boris Johnson from suspending Parliament?

Boris Johnson would face plenty of hurdles if he tried to prorogue Parliament in order to force through a no deal Brexit. Sir John Major has added a new one, saying that he “would be prepared to go and seek judicial review to prevent Parliament being bypassed”.

Supporters of the Johnson campaign have been quick to call this “a stunt”, “completely bonkers” and “completely mad”. But they should not be too quick to dismiss the idea of a legal challenge. It might turn out to be successful – but it would be much better if we never got the chance to find out. Such a court case would be politically and constitutionally ugly, and could only ever happen if a new prime minister had shown an irresponsible disregard for Parliament.

Lawyers disagree on whether proroguing to stop no deal would be a lawful use of executive authority

The prorogation of Parliament is a two-stage process. The Prime Minister advises the monarch to prorogue, and then the monarch exercises her power under the royal prerogative – the last vestiges of the powers enjoyed by the Crown – to prorogue. Any legal challenge is more likely to focus on the minister’s advice than on the Queen’s decision, and the High Court would be invited to declare that such advice was unlawful. There might even be an attempt to ask the courts in advance whether such advice would be lawful.

Opinion is divided as to whether such a challenge would succeed. Lord Pannick QC, who successfully argued before the Supreme Court that an Act of Parliament was needed to trigger Article 50, has suggested that the court would likely rule such a prorogation unlawful. This is because a prime minister would be trying to bypass Parliament on an issue of “significant constitutional importance” – and trying to evade Parliament precisely because MPs have previously said they want to prevent a no deal Brexit.

Others disagree. Professor John Finnis QC argued in favour of prorogation when the House of Commons was wresting control of the parliamentary timetable from the Government in order to outlaw no deal in April. There is some doubt over whether prorogation could even be the subject of a judicial review and, moreover, unlike with the Article 50 case – in which the Supreme Court ruled that rights brought into law by the 1972 European Communities Act could not be removed by prerogative powers – it is not immediately obvious what rule of law the Government would be frustrating.

Parliament could legislate to make prorogation harder – though that comes with its own constitutional headaches

If Parliament legislated to indicate its opposition to either no deal Brexit or prorogation, then any prime minister would be on much shakier ground advising the Queen to prorogue in order to bring about a no deal. So far, however, Parliament has not done so. In the European Union (Withdrawal) (No. 5) Act 2019, Parliament made clear its opposition to a no deal Brexit on 12 April – but that deadline has been and gone. Parliament has also passed a number of motions opposing no deal, but these do not have the force of law – and none relate to the 31 October deadline.

MPs have been trying to change this. Dominic Grieve MP, the pro-EU Conservative backbencher, proposed several amendments to the Northern Ireland (Executive Formation) Bill so that the threat of prorogation would be “banged on the head”. But the only amendment which passed was one requiring the Government to report on the progress of Northern Ireland power-sharing talks every two weeks from 9 October to 18 December. While that does not itself rule out prorogation, it might make a legal challenge to prorogation a little stronger as the Government would not be able to meet its statutory duties to report to Parliament unless Parliament were sitting.

Even if a majority of MPs backed a bill which more explicitly prevented a prime minister from proroguing Parliament, a constitutional wrinkle would remain. Erskine May, the parliamentary bible, says that bills affecting the royal prerogative (including the prerogative to prorogue Parliament) require “Queen’s consent”. This means that, before the bill can become law, a Privy Counsellor – who is usually a serving minister – must indicate the consent of Her Majesty. Her decision is not open to challenge in court and, since the Queen is likely to act on the advice of her ministers, a Boris Johnson government could try to use that advice to veto any anti-prorogation legislation.

However, it is ultimately up to the Speaker whether Queen’s consent is required and, if the Government is ripping up convention to use it as a veto against a majority of the House of Commons, the Speaker might start ripping up convention too. Even if the Government succeeded, it could encourage the courts to control the Government’s exercise of the prorogation power and make a legal challenge more likely to succeed.

Even if proroguing were lawful, it would still be unconstitutional

Sir John Major’s threat is not hollow. A prime ministerial attempt to prorogue Parliament, and to bypass its opposition, would be grounds for a legal challenge – even though there are no guarantees that such a challenge would succeed.

However, the United Kingdom’s ‘political’ constitution comprises not only rule of law, but also conventions and principles that cannot be enforced by the courts. Proroguing Parliament to secure a no deal Brexit by bypassing the clear opposition of the House of Commons would, without a doubt, be highly improper.

Proroguing to avoid a possible vote of no confidence, which could well await a new prime minister intent on a no deal Brexit, would be even worse.