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Jack Williams: The Supreme Court’s Approach to Prerogative Powers in Miller: An Analysis of Four E’s

jack-williamsThree initial observations can be made about the Supreme Court’s analytical approach to prerogative powers in the Miller judgment.

First, the Court’s judgment has clarified the proper framework for analysing prerogative powers. After establishing that a relevant prerogative power exists (see [34] and [54]), the next stage is to determine the extent of that prerogative power. This comes before any possible questions of abrogation by statutes arise. Thus, the Court delimited prerogative powers generally, and the foreign relations treaty prerogative specifically, in holding that such executive powers cannot affect domestic law or domestic rights (see [40] – [57]). As such, the third theoretic step (exclusion by statute i.e. the abrogation line of authority such as de Keyser’s) and the fourth step (control of the exercise of such prerogative power) became unnecessary once the Court found that domestic law and rights would be affected if and when Article 50 were triggered (see [60] – [89]). As the Court stated “rather than the Secretary of State’ being able to rely on the absence in the 1972 Act of any exclusion of the prerogative power to withdraw from the EU Treaties, the proper analysis is that, unless that Act positively created such a power in relation to those Treaties, it does not exist” ([86]).The Court could not find such positive authorisation in any of the relevant statutes from 1972 to 2015.

Second, the Supreme Court upheld the Divisional Court’s two-pronged reasoning that prerogative power does not extend to either changing domestic law or affecting domestic rights (see [83]). This may have significant consequences for the use of prerogative powers in the international sphere where domestic or acquired rights would be affected, and is of potentially wider application than if the Court had confined its analysis to circumstances where acts on the international stage result in changes to the (domestic) constitutional framework. It may, combined with the findings in relation to the principle of legality ([87]), have implications for what the authorisation bill needs to cover.

Third, we learn that the “frustration of purposes” line of authority (e.g. FBU) falls within the remit of extent analysis (that is a red-line parameter around what prerogative powers can ever do), rather than as a matter of exercise control (that is as one factor within discretionary control of using prerogative powers such as abusive or irrationality or proportionality control): see [51]. This, it seems to me, is more stringent than Laker, FBU and the Divisional Court judgment in Miller could be read as. What we do not learn, however, is the interrelationship between the Bill of Rights tests of dispense/suspend (which, it seems, falls within the extent analysis stage) and the exclusion stage (that is abrogation) tests. This is unfortunate, and could readily herald a more stringent approach by expanding the extent analysis box (i.e. extending inherent limitations on the prerogative) and thus reducing the scope for getting to the exclusion-by-statute analysis.

Jack Williams is a Barrister at Monckton Chambers. He was instructed in the Miller litigation at both Divisional Court and Supreme Court levels by Bindmans LLP on behalf of the Pigney Respondents/Interested Parties (known as “The People’s Challenge”). All views are strictly his own and do not necessary represent those of either his clients or the rest of Monckton Chambers.

(Suggested citation: J. Williams, ‘The Supreme Court’s Approach to Prerogative Powers in Miller: An Analysis of Four E’s’, U.K. Const. L. Blog (25th Jan 2017) (available at

4 comments on “Jack Williams: The Supreme Court’s Approach to Prerogative Powers in Miller: An Analysis of Four E’s

  1. martycaine
    January 25, 2017

    I do agree with the Supreme Courts decision not to back government in this matter as the precedent set by doing so, would have been rather worrying. Parliament must always be able to hold government to account on anything that will eventually change the rights of the people. However, that is something that will only occur after the negotiations are concluded, not because of the invoking of Article 50.

    The notification to the EU which automatically invokes article 50 changes nothing other than initiates the exit negotiations. However when that happens surely only EU law will apply as there is nothing in UK law that covers this event, even the EU Referendum bill fell short of actually detailing what should be done once the referendum result was determined. As the rules of procedure dictates negotiations are between the EU and the UK government, does this mean that parliament will have no further opportunity to interfere with the exit negotiations once Article 50 has been invoked?

    Another thing that puzzles me about the Gina Millar case is what did it actually achieve? Other than causing a delay that the government seems to have wanted anyway, as government holds 329 of the 650 seats in Parliament it seems extremely unlikely that any bill in regards to this will not get passed by parliament. The Lords, I hope are fully aware that if they try to overturn the democratic decision made by the people, it will only lead to the abolition of the House of Lords. So other than a deliberate delay tactic, I fail to see what the whole Gina Millar case actually did achieve.

    • CY
      April 5, 2019

      Hi, I am a new constitutional law student and I do not understand what did you mean by “As the rules of procedure dictates negotiations are between the EU and the UK government, does this mean that parliament will have no further opportunity to interfere with the exit negotiations once Article 50 has been invoked?” on the second paragraph
      Could you explain what did you mean by that as I think it will be very helpful in my exam if I understand it better.
      Thank You.

  2. Peter
    January 26, 2017

    In my opinion the Court missed the opportunity to make it clear that the powers of the executive to act without parliament only exist when the exigencies of the situation required, such as in times of war.
    Secondly with regard to the EU treaties the court and indeed the respondents did not give sufficient regard to the fact that EU laws over the past 44 years created not only rights but obligations. The 1972 Act created delegated legislation.
    This is very different from normal treaties where – absent any supporting statute – the defendant in an action in an international court is always the government on the ground that it signed the treaty. The 1972 Act created many obligations upon UK persons which had the court decided in favour of the government would have created real confusion. Thus for example what would happen if I had continuing obligations to my neighbour under a law from Brussels? The chaos that a judgment in favour of the government would have created would have been considerable.

  3. Pingback: Robert Craig: Miller: An Index of Reports and Commentary | UK Constitutional Law Association

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