Key points

  • The referendum result is advisory only and not legally binding but the UK government has committed itself to Brexit implementation (although this does not bind Parliament or future governments) and has established 2 new departments of state (for EU exit and international trade).  
  • The government believes it is entitled to give notice under Article 50 as a matter of prerogative power, without parliamentary approval or legislation.  
  • Parliament will have a heavy workload with detailed legislation to prepare the UK legal system for the removal of its EU legal foundations at the date when Brexit eventually takes effect.  
  • At least one legal challenge seeks to assert that prior parliamentary approval is required before Article 50 can be triggered. The government, however, appears committed to proceeding without a substantive vote in the House of Commons or Lords which might frustrate their plans to trigger Article 50 or their negotiation of the withdrawal and the new UK/EU relationship.

The legal status of the referendum result

The legal status of the referendum of 23 June 2016 is clear. It is ‘advisory’ and does not, of itself, trigger the Article 50 process or bind the UK government or Parliament.

Section 1(1) of the European Union Referendum Act 2015 states: "A referendum is to be held on whether the United Kingdom should remain a member of the European Union". There is no binding commitment to implement the decision – the wording of the Act does not give any indication as to what must happen next. [1] 

This view has been reiterated by academics:

"The EU […] Referendum is a creature of the European Union Referendum Act 2015. There is no requirement in the Act that the UK Government implement its results, nor does the statute set any time limit for implementing a vote to leave the EU. It is a pre-legislative, or consultative, referendum, enabling the electorate to express its opinion before any legislation is introduced. The 1975 referendum on the UK’s continued membership of the EEC was also an example of this type."[2]

Political commitment to Brexit

Before the referendum, David Cameron had indicated that his government would implement a vote to leave by triggering Article 50 (a logical approach given that his government had instigated the referendum). Since the referendum, Theresa May has committed her government to pursue and deliver Brexit. It is regarded as a political obligation to carry out ‘the will of the people’. Two new departments of state have been established - the Department for Exiting the EU (under David Davies) and the Department for International Trade (under Liam Fox).

In theory, at least, these decisions do not bind future UK governments or Parliament.

Giving notice to the EU and the role of the UK Parliament

Article 50 TEU provides that "any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements." The question has arisen whether the UK government is entitled to give notice under Article 50 without any approval or legislation by Parliament.

Following the referendum result several commentators and lawyers have questioned whether the Prime Minister can trigger Article 50 unilaterally. Three constitutional lawyers [3] published an article that contends an Act of Parliament is needed to approve the triggering of Article 50. They argue that if the Prime Minister were to "attempt to do so before such a statute was passed, the declaration would be legally ineffective as a matter of domestic law and it would also fail to comply with the requirements of Article 50 itself".

A recent House of Commons Library briefing paper [4] advanced the four main arguments:

  • Government’s ‘prerogative’ power. On this view, government would be able to act alone to trigger Article 50. The justification is that government has ‘prerogative power’ to conduct foreign affairs – this includes the power to withdraw from a treaty or international organisation such as the EU.   
  • Parliamentary involvement. On this view, there may be a political case for involving one or more houses of Parliament to approve the decision to trigger Article 50. The justification is political rather than legal – "there is no explicit requirement in the UK's constitutional arrangements for parliamentary approval of a decision to notify the EU." [5]
  • Order in Council. On this view, Article 50 must be triggered by government by making an Order in Council. Section 2(2) of the European Communities Act (ECA) 1972 is cited as justification for this position.
  • Act of Parliament. On this view, an Act of Parliament is required to trigger Article 50. The justification is that prerogative power may only be exercised where it does not conflict with an existing Act of Parliament – i.e. the ECA 1972. [6]

Some of those who take the view that Parliament must be involved in the process are to take legal action. The fact that the advisory nature of the referendum was the deliberate choice of Parliament and that the result has not triggered Article 50, is seen as further grounds for concluding that a decision of Parliament is now required. The government continues to assert that it is able to trigger Article 50 without prior approval or legislation from Parliament. It is hoped that the Courts can hear the case, and any appeal to the Supreme Court, before the end of the year. If the decision is that the government’s position is consistent with the UK constitution, the question of a possible reference to the CJEU, for an interpretation of Article 50, may not arise.

It is clear that in due course Parliament would have to pass a mass of detailed legislation to prepare the UK legal system for the removal of its EU legal foundations at the date when Brexit eventually takes effect. Constitutionally, it will have to repeal the ECA 1972.

A recent House of Lords European Union Committee Paper [7] argued that parliamentary scrutiny of the Brexit negotiations will be critical to their success. The referendum did not address any of the practicalities and difficulties that are now being confronted in the Brexit negotiations nor did it address the question of the UK’s preferred post-Brexit relationship with the EU.

The government, however, appears committed (subject to the outcome of the challenge above) to proceed and to give notice under Article 50 without a substantive prior vote in Parliament, which might frustrate their plans to trigger Article 50 or their intended negotiation of the withdrawal and the new UK/EU relationship.

Recent statements from the government have focused on their view that the House of Lords has no rights to block or delay the government’s plans to implement the referendum result. In the immediate aftermath of the referendum, it appeared that some members of the ‘remain’ campaign thought that if there were a vote in the House of Commons before Article 50 notice was given, this would result in Brexit being blocked (on the basis that a majority of MPs were believed to have supported remaining in the EU during the referendum campaign). It is difficult to predict the political mood in these uncertain times, but it now seems that if there were to be a vote, some of these MPs would now be reluctant to block Brexit outright because it would be seen as refuting the ‘will of the people’ and, in the case of the Conservatives, defying their own government. [8]