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Home / News and Insights / Blogs / Brexit / 72: Brexit – Miller No.2 in the Supreme Court – that’s my prerogative?

The Supreme Court sat for three days this week to hear arguments about whether the Prime Minister’s advice to the HM Queen to prorogue parliament was unlawful. In this post, we summarise the submissions made before the court.


The case is an appeal from two decisions, R (Miller) v Prime Minister in the High Court of England and Wales (known as Miller No.2 to distinguish it from the 2016 case by the same claimant), and Joanna Cherry MP and others for Judicial Review from the Scottish Inner House of the Court of Session.

It was argued by the claimants in both cases that the Prime Minister’s advice to the Queen to prorogue parliament was an unlawful abuse of power being substantially influenced by extraneous and improper considerations, such that the court had a duty to intervene.

But the courts reached different conclusions. The High Court held that the decision of the Prime Minister to seek the prorogation of parliament – an exercise of a prerogative power – was not justiciable as it was an exclusively political matter. The court also declined to recognise the concept of Parliamentary Sovereignty as generally including parliament’s right to conduct its business unimpeded. Conversely, the Scottish Court looked first at the circumstances surrounding prorogation, concluded that Prime Minister had advised prorogation for the improper purpose of ‘stymieing parliament’, and so held it to be unlawful, notwithstanding that it was a prerogative power.

Day 1

Miller was represented by Lord Pannick QC, who submitted that, while the Prime Minister clearly had a right to prorogue parliament to present a Queen’s Speech, in this case, the Prime Minister suspended parliament to avoid the risk of MPs ‘frustrating or damaging’ his Brexit plans. The ‘exceptional length’ of this suspension (9 Sept to 14 Oct, ie 5 weeks) was ‘strong evidence the Prime Minister’s motive was to silence parliament because he sees parliament as an obstacle’. For the executive to use a prerogative power to seek to evade control by parliament ‘stands the basic principles of constitutional law on their head’.

In the afternoon, the Advocate General for Scotland, Lord Keen QC argued on behalf of the government in its appeal against last week’s Court of Session ruling. Lord Keen submitted that previous prorogations of parliament for political purposes had ‘clearly been employed’ when governments wanted to ‘pursue a particular political objective’ and when the government of the day lacked majority, adding the government was ‘entitled to do so’. Accordingly, it was not for the courts to decide what is, and what is not, a ‘legitimate political reason’. If MPs did not want parliament to be suspended, they had ‘adequate mechanisms’ and opportunities to stop prorogation by passing new laws, citing EUWA No. 2 2019 as an example (passed in just two days).

Day 2

The government answered the case made by Lord Pannick. Sir James Eadie QC argued that proroguing was ‘a well-established constitutional function’ and a ‘prerogative power that has been expressly preserved by parliament’. Ending and starting parliamentary sessions are the government’s decision and ‘such decisions are inherently and fundamentally political in nature’. Previous examples (pulled from this House of Commons briefing paper) were cited to demonstrate there are no hard and fast legal rules over how long parliament should be prorogued:

  • 1914 (total of 53 calendar days) – World War One;
  • 1930 (total of 87 calendar days) – fallout of the 1929 Wall Street Crash and onset of the Great Depression; PM of the day, James Ramsey McDonald, did not have a majority; and
  • 1948 (twice in the same year, for two non-consecutive days) – to amend the 1911 Parliament Act without the House of Lords’ consent.

Sir James submitted that dissolving parliament has always been a non-justiciable matter and there was no difference with proroguing: both were political rather than legal matters, and therefore non-justiciable. The claim that the Prime Minister prorogued parliament to ‘stymie’ it (the word used in the Court of Session judgment) was ‘untenable’.

Many media commentators (see eg here) noted that there was a lack of witness statements from the government or official explanation as to how the decision to prorogue was made. Lord Wilson stated that it was ‘odd that nobody has signed a witness statement to say, this is true, these are the true reasons for what was done’.

In the afternoon, Aidan O’Neill QC, representing Joanna Cherry MP and others, argued the following:

  • the label of ‘prerogative’ applied to a disparate collection of powers, and did not supply additional ‘heft’. In Sandiford, the Court of Appeal ruled that, in some circumstances, such powers were justiciable (although the Supreme Court rejected a challenge to the government’s refusal to use prerogative powers in that case);
  • the Prime Minister’s action in proroguing parliament had the intent and effect of preventing parliament, impeding it, from holding the government politically to account at a time when the government was taking decisions which would have ‘constitutional and irreversible impacts’ on the UK. That fundamentally altered the balance of our constitution by allowing the Executive to govern without the proper constitutional accountability. parliament didn’t legislate to block prorogation, time was not on their side, and even so, not legislating also does not mean they consented to being prorogued;
  • the government’s failure to provide a witness statement allowed the court to draw ‘adverse inference of fact’. Documents submitted to the court should not be considered ‘gospel’ or the ‘complete truth’ and that the government could not be trusted to not use ‘low, dishonest, dirty tricks’;
  • the courts could determine whether the power of prorogation has been exercised lawfully by the government. In this case, ‘the true dominant purpose of prorogation was, as the Inner House correctly observed, to stymie parliamentary scrutiny of the executive regarding Brexit’; and
  • the Supreme Court should intervene to rebalance the constitution.

Day 3

The four interveners made their case on Thursday.

Lord Advocate James Wolffe QC on behalf of the Scottish Government submitted that the ‘fundamental principle’ of the British constitution – parliamentary accountability – was at stake. The government’s prorogation of parliament was ‘an abuse of executive power which calls for the intervention of the court’ and would have ‘a profoundly intrusive effect’ on the ability of parliament to scrutinise the executive. He distinguished prorogation and dissolution: the former maintained the government in office ‘without the mechanisms of accountability to parliament’; the latter required MPs to give up their seats, with decision-making put back to the electorate.

Ronan Lavery QC, on behalf of Northern Ireland peace campaigner Raymond McCord, emphasised the EU’s role in the peace process, enabling close co-operation between the UK and the Republic of Ireland. He also argued it prevented parliament from scrutinising the secondary legislation necessary to deal with Brexit, which impacts would be felt particularly in Northern Ireland.

Mike Fordham QC, for the Welsh Government, argued that the prorogation ‘consciously and purposely impeded the constitutional principle of parliamentary sovereignty’, and ‘impeded the ability of the National Assembly for Wales to engage in dialogue with the Westminster Parliament’.

Lord Garnier QC, for Sir John Major, submitted that the documents submitted by the government did not provide the true reason for prorogation; it was ‘motivated by a desire to prevent parliament interfering with the Prime Minister’s policies during that period’. The Court had to consider whether that caused ‘material interference’ with parliament’s role.

Counsel for the appellants, Lord Keen QC (for the government against Joanna Cherry SNP) and Lord Pannick QC (for Gina Miller) then closed the hearing.

Lord Keen QC stated that the Supreme Court was being invited to ‘control the length of the prorogation of parliament’, which was a matter of constitutional convention, not statute, and which the court was not properly equipped to deal with. Further, if parliament had wanted to legislate on this matter, they had the ‘tools available’ and could have done so. Third, prorogation was very similar to dissolution and, as dissolution is non-justiciable, so is prorogation. Fourth, parliament could have blocked prorogation with a motion of no confidence; this wasn’t done because the Opposition didn’t see it as politically advantageous.

On remedy, Keen argued that, if the Court determined that prorogation was unlawful, then it should be for the government and parliament to decide the remedy, not the Court. That approach was supported by precedent (see Unison judgment). Asked how parliament could respond if it wasn’t sitting, Keen replied that, in the first instance, it would be for the government to respond. Further pressed on what the PM would do if he lost the appeal, Keen concluded that ‘it is not for the executive to give undertakings to the court’, and the Prime Minister should be given a ‘broad margin of discretion’.

The government had initially refused to disclose its written submissions on relief to the media. But Jo Maugham QC, the barrister and director of the Good Law Project tweeted images of the statement, on the basis that, once submissions are made in open court, they can be disclosed. Point 3 states the Prime Minister may consider proroguing parliament again or continuing prorogation until 14 October, even if the Supreme Court found against the government.

In summing up, Lord Pannick QC said:

‘This prorogation has prevented parliament from carrying out its scrutiny of the executive at a time when the constitutional principle of the Executive being answerable to parliament is of vital importance.’

There was ‘no other rational reason’ for the prorogation for a ‘period of exceptional length’, and this amounted to prorogation being used for an improper purpose. ‘The executive, the junior partner, cannot claim some unfettered power to close down the senior partner.’

Pannick submitted that, if the Supreme Court found the advice was unlawful, then a declaration should be made for:

  • parliament to reconvene, speedily, hopefully next week;
  • parliament to declare the prorogation as null and void, if appropriate; and
  • if the Prime Minister ignores the court’s declaration of illegality, then the Speaker of the House of Commons and Lords Speaker to begin internal proceedings to reassemble parliament – the PM did not have to do anything – and no legal challenge could be made against parliament on how it decides to proceed or what happens next.

Lady Hale closed, noting ‘none of this is easy’ and stating the court hoped to make its ruling ‘early next week’.

‘I don’t need permission, Make my own decisions, That’s my prerogative’ (Bobby Brown, My Prerogative)

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