05 April 2019

With the Prime Minister serving notice on her time in Downing Street, Joe Marshall asks whether Labour can be confident of any commitments she makes on the UK’s post-Brexit future.

Having been invited to work with Theresa May on a plan to break the Brexit impasse, Jeremy Corbyn comes armed with a shopping list of demands. These include a commitment to a permanent customs union, ensuring the UK keeps pace with EU employment and consumer rights and demanding a greater role for Parliament in the next stage of negotiations.

The Prime Minister will no doubt listen, and perhaps she will even be convinced to compromise. But that would be just the first part of the Labour leader’s challenge. If Corbyn were to help her to get a Brexit deal over the line, how can he be sure that the PM’s successor will deliver those commitments?

There are several routes to ensuring the Prime Minister's commitments aren't dropped   

  1. Negotiate changes to the Political Declaration

The EU has said that it is open to redrafting the Political Declaration, so this could be the place for new commitments on the future relationship. This would have political force, but the Political Declaration is not legally binding and could ultimately be ignored.

  1. Negotiate changes to the Withdrawal Agreement

A more secure route would be to include commitments in the legally-binding Withdrawal Agreement Indeed, the Withdrawal Agreement already includes some non-regression commitments on social and environmental standards and on state aid.

However, including further commitments in the Withdrawal Agreement is unlikely. Both the Prime Minister and the EU are adamant that the Withdrawal Agreement in not for renegotiation, and the Withdrawal Agreement is not supposed to set out the future relationship.

  1. Use domestic legislation

It is more likely that the Prime Minister will offer to legislate for commitments in the Withdrawal Agreement Bill (WAB) – the piece of legislation that will implement the Withdrawal Agreement in domestic law.

The Government has already promised Labour MPs that it will include commitments on worker’s rights and Parliament’s role in future negotiations. It has also suggested it will legislate to require MPs to formally approve entering the Irish border backstop, and may now be considering a ‘devo lock’ which would require a future Prime Minister to secure the consent of Scotland, Wales and Northern Ireland before they can alter the UK’s future relationship with the EU. But these commitments risk turning the Withdrawal Agreement Bill into a ‘Christmas tree’ bill of commitments. By appeasing one set of critics at the expense of another, the bill's passage through Parliament could more challenging.

Some commitments in the Withdrawal Agreement Bill may not even be enforced by the courts. For instance, it would be constitutionally unusual to give the courts a role in policing the Government’s approach to future negotiations, or in enforcing any government commitments to report to MPs on its progress towards negotiating objectives. The effect of legislating may simply be to add political pressure rather than legal teeth.

Attempting to make it harder for a future Parliament to change the law will be difficult, if not impossible

Any commitments in domestic law could be reneged on by a future government with a parliamentary majority. The Government is aware that the UK has no mechanism to prevent one Parliament overturning a decision of its predecessor – or at least one that has been affirmed by the courts. Previously it has proposed that provisions on repealing citizens’ rights would require ‘an additional procedural step’ beyond a simple majority in Parliament. The Government has yet to say what that step might be, but additional hurdles could include a requiring a supermajority, a referendum or the need to consult the devolved governments.

Even still, nothing would be watertight. It remains unclear whether the courts would uphold any additional legislative hurdles on future Parliaments which could challenge the traditional view of parliamentary sovereignty.

For their part, the courts could recognise the Withdrawal Agreement Bill as a ‘Constitutional Statute’. This would make the Act immune from implied repeal – which means that a more recent piece of legislation takes precedence if there is a conflict. Constitutional Statutes can only be overruled if the later statute makes that clear in its wording. But it is not easy to pre-empt how the courts would respond.

Labour might have to rely on politics rather than the law

Enshrining promises in legislation can provide some protection against change by a future government and could have symbolic value. However, a future government with a parliamentary majority may well be able to override these commitments, and any attempt to use novel or untested legislative techniques to prevent it could end up with the courts facing difficult questions about the nature of parliamentary sovereignty.

So, if Jeremy Corbyn wants to ensure a future government does not tear up commitments made by the Prime Minister, his best tactic appears to be to win, and keep winning, the political argument. Perhaps fittingly with the Brexit process, however, nothing would be guaranteed.


In addition to these approaches can also build it into the EU negotiating process. Establish with the EU a conditional timetable with Reviews to take stock; sign off different elements eg backstop; trade deal etc; and see if future timetable needs to be amended - including shortening.

The advantage of this is that it would enable a framework to be built into which parliamentary scrutiny could also be built. And when each element is sorted it can be signed off and parliament tied into each element. So, won't have to wait until end and presented with all the outcomes as a fait accompli.

The other advantage is that this is the approach that the EU followed when, as it became more centralised around the Single Market, it managed the divergence of its ex-colonies. Then too, as now, there was an unsatisfactory initial deal - the Lome Agreement - but it turned out to be a lead into the sort of process described above with the Cotonou Agreement. So, not only does the EU have history in this approach it also succeeded - without friction and largely unnoticed. One other aspect it might be worth inserting in one part of the timetable - the Annual Review - is an independent adjudication panel to act as a sort of multi-national small firms court to deal with snags and frictions.

The possibility of negotiating changes to the Withdrawal Agreement is dismissed above as being “unlikely”. Before Labour gives up on this more secure route of establishing a so-called ‘Boris lock’, ought they not completely exhaust this possibility with EU-27 negotiators and in trying to achieve a domestic Parliamentary majority? A lengthy extension to the Article 50 process could open up the opportunity of pasting Labour’s preferred softer version of Brexit into the Withdrawal Agreement as a replacement to the Irish Backstop. (If required to pacify EU-27 negotiators, the current backstop protocol could remain effectively as the backstop to the new backstop.) Resistance to this approach from the Conservatives would expose their latent plans to regress to a much harder Brexit in the future.

I don't think there is a watertight legal way of Corbyn getting a lock on the Brexit final status deal - and nor should there be. Another way of adding political weight to a May-Corbyn proposition for Brexit is to use a confirmatory referendum, but with an amended Political Declaration to signal the intent about having a permanent customs union. This would give a second rationale for the People's Vote; (1) to check whether there is an appetite for any Brexit compared to a specific Brexit; (2) to underpin more enduring political support for a particular form of Brexit - a customs union for example - if that option turns out to be the newly expressed will-of-the-people.