In its judgment on 3 November (R (Miller and Dos Santos) v Secretary of State for Exiting the European Union), the Divisional Court emphatically found that the Government "does not have [the] power"—without Parliamentary say-so—to trigger the UK's withdrawal from the EU.

The judgment itself reflects the unique status of EU law in our domestic legal order.

That status, and the domestic law rights of citizens to which it has given rise, were conferred by Parliament (by passing the European Communities Act 1972), and, the Court held, cannot be defeated without the express consent of Parliament. See further our media comment.

As anticipated, the Government has said it will appeal to the Supreme Court and a hearing is expected to start on 7 December. While the three very senior judges who heard the case were unanimous in their conclusions, and it is clear that they did not regard this as a finely-balanced case, the Government has said publicly that it believes that it has strong grounds of appeal and is confident that the Supreme Court will overturn this decision.

The Court stated that it was not concerned with the political issue of the merits of leaving the EU and that the matter before it was a "pure question of law". That is undoubtedly so, and the Court rightly approached it on that basis. However, the consequences of the Court's decision are acutely political.

Shortly after the Court's decision, Mark Carney, the Governor of the Bank of England, suggested that the decision would likely add to, and prolong, economic uncertainty in the UK. The Governor's comments were echoed by Dutch Finance minister Jeroen Dijsselbloem, who said that the decision would lead to "more uncertainty on the outcome and the timeline [for Brexit]," which would be to the detriment of business in the UK and Netherlands. The Government, however, has asserted that its timetable for Brexit remains unchanged.

The implications of the judgment are also practical. This blog addresses the following practical questions, which will be of direct concern to many businesses seeking to navigate through the Brexit process.

  1. Will Parliament need to pass legislation in order for Article 50 to be triggered?
  2. What is an 'Article 50 Bill' likely to say, and will Parliament now dictate the UK's negotiating position?
  3. How long will it take a Bill to pass through both Houses of Parliament?
  4. Ultimately, will the Prime Minister be able to trigger Article 50?

Will Parliament need to pass legislation in order for Article 50 to be triggered?

On Thursday, the Court indicated that it would make its decision as to the "precise form of the declaratory relief to be granted" at some point this week. That may make clear whether the only way that the Government can proceed is by way of primary legislation, or whether a vote on a motion would suffice.

Traditionally, the Court has been reluctant to instruct Parliament to introduce legislation. In R (Wheeler) v Office of the Prime Minister, for example, the Court made clear that the introduction of Bills into Parliament was a privilege and a matter for MPs. There is, therefore, a possibility that the Court's declaration will confirm that the Government does not have the power to trigger Article 50 in the absence of Parliamentary consent, but will not specify the form of consent required.

In such circumstances, the Government could seek to hold a vote on a motion, and avoid introducing primary legislation. Motions can, in general, be passed in a short time frame without the multiple stages of scrutiny to which Bills are generally subjected. Importantly, the Government would also have discretion as to whether to allow the House of Lords a vote on the motion. Previously, motions have been used to obtain Parliamentary consent for politically charged matters (for example, the invasion of Iraq in 2003), although none as constitutionally significant as the decision to leave the EU.

Notwithstanding its reticence to trespass on Parliamentary matters, the High Court made clear, during the hearing that it considered the means by which Article 50 was triggered to be justiciable; and suggested that it was within the Court's discretion to declare that primary legislation was required.

The indications, and the logic of the judgment, make it unlikely that anything but an Act of Parliament would suffice. David Davis, Secretary of State for Exiting the European Union, appeared to acknowledge this, saying "we are presuming [the ruling] requires an Act of Parliament, therefore both Commons and Lords".

What is an 'Article 50 Bill' likely to say, and will Parliament now dictate the UK's negotiating position?

We do not yet know what the Bill, empowering the Government to trigger Article 50 (the "Article 50 Bill"), will say. It could be extremely brief. Jacob Rees-Mogg MP has suggested that the Bill "need not run to more than a couple of clauses;" and could, for example, simply state that the Government shall trigger Article 50 at such time as it desires.

The House of Lords Select Committee on the Constitution (the "HLSCC") published a report on the invoking of Article 50 in which it made clear that Parliament could simply enact a Bill that recognised and accepted the result of the referendum, but made clear that Article 50 was to be triggered when the Government considers that it "is in the UK's best interests to begin the formal two-year negotiation process."

It seems unlikely, however, that a Bill in such a form would pass through Parliament unamended.

The Liberal Democrats have made clear that they would seek to introduce amendments to the Bill, in order to force the Government to pursue a so-called 'soft Brexit'. Owen Smith MP, has said that the Labour party may seek to force a referendum on the final agreement between the UK and the EU; and it is almost certain that the SNP would seek to amend the legislation to give the devolved assemblies a formal role in the process of leaving the EU.

More broadly, it is likely that Parliament will demand close scrutiny of the negotiations. The Government has been keen to avoid giving a running commentary on its proposed negotiations with the EU but it will inevitably face calls to open up as a condition of Parliament's support.

The HLSCC suggested in its report that the Article 50 Bill should set out the framework for Parliamentary scrutiny of the withdrawal process. This framework could include provisions requiring: (i) the Government to report to Parliament at defined stages; (ii) the Government to seek Parliamentary approval of its negotiating objectives and 'redlines'; or (iii) the Government to satisfy certain preconditions (such as obtaining an agreement from the EU that it will protect the status of UK citizens living in the EU) before it is able to trigger Article 50.

Interestingly, the HLSCC report suggested that Parliament would strengthen the Government's negotiating hand by enacting such a framework.

While there seems little prospect that the Act would impose strict limits on what the Government can negotiate — the suggestion that it could require a so-called soft Brexit defies the reality of the negotiating process — the market reaction to the judgment, as sterling rose to a four-week high, suggests strongly that Parliamentary involvement would heighten the chances of a soft Brexit.

How long will it take a Bill to pass through both Houses of Parliament?

Timing is likely to be a function of politics more than procedure. Parliament is capable of passing legislation exceptionally quickly. The Anti-terrorism, Crime and Security Act 2001 passed both Houses of Parliament in less than a month; and emergency legislation, such as the Data Retention and Investigatory Powers Act 2014, can be passed in a matter of days.

David Natzler, the Clerk of the House of Commons, has noted previously that "it is a generally observed convention that Bills of 'first class constitutional importance'…are committed to a Committee of the whole House [of Commons]." This means that all "650 members become a committee so that all Members can table amendments and take part in debate and decision on the details of the Bill." Although it is arguable that an Article 50 Bill would fall into this category, the Government would be likely to seek a more streamlined process.

While the Government has a majority in the House of Commons, it has no such majority in the House of Lords and the latter may be unlikely to agree to a significantly expedited legislative process. The vast majority of peers supported remaining in the EU. Moreover, the Upper House generally considers itself to be a consultative and revisionary chamber and its members do not have the same electoral considerations that MPs have. It is no surprise, therefore, that the Conservative peer Patience Wheatcroft said on Friday “I think it is only right to delay triggering Article 50 until we have a clearer idea of what it actually entails. And I think there will be others in the Lords who feel the same way.

The Government may try to argue that House of Lords is bound by the Salisbury Convention, which provides that the Upper House will not block Bills provided for in a Government's manifesto. The Conservative manifesto at the last General Election did contain a brief reference to the Government's post-referendum conduct, but it is unlikely that the Lords, which has taken an increasingly narrow view of the Salisbury Convention, would accept that it is triggered by the general wording of the manifesto.

Will the Prime Minister be able to trigger Article 50?

It is almost unthinkable that an Article 50 Bill would not ultimately pass through Parliament. If it did not, there would at a minimum be an immediate political consequence in the form of a general election and potentially a much wider constitutional crisis.

MPs of all persuasions appear to accept that the UK must now leave the EU; and while the House of Lords is likely to cause the Government delay it would be an extremely bold House of Lords that decided to block an Article 50 Bill.

However, the relevant questions are; (i) how long will the Prime Minister have to wait to be able to give notice to the European Council; and (ii) how much of a free hand will she have around the negotiating table?

A tweet from Andy Burnham MP sums up the Government's situation quite nicely, "Memo to my constituents: I will never vote to block Brexit. But I simply don't trust Boris Johnson to negotiate on behalf of the North West."