Throughout the Brexit saga, one thing I’ve heard repeatedly is that due to the principle of parliamentary sovereignty, referendums are not legally binding:

Parliamentary sovereignty is a principle of the UK constitution. It makes Parliament the supreme legal authority in the UK, which can create or end any law. Generally, the courts cannot overrule its legislation and no Parliament can pass laws that future Parliaments cannot change.


Many groups have pushed for a second Brexit referendum to help resolve the current impasse, but it’s not unreasonable to worry that the political pressures that have prevented Parliament from reaching a majority in favor of any plan might persist even after another referendum, particularly if the result is close.

Is there any way that Parliament could tie their own hands by either:

  1. creating a legally binding referendum whose result would guarantee specific actions that Parliament could not change or delay

  2. or, if that's impossible, make the chosen decision the default, such that Parliament would have to take specific action to overrule it?

3 Answers 3


No they cannot for exactly the reasons you cite. Even if parliament were to pass a law saying that the referendum results were binding, a future parliament could repeal that law.

  • Could they at least make it so that the chosen option is the default, such that they would have to find a majority to explicitly overrule the referendum result?
    – divibisan
    Nov 8, 2019 at 16:47
  • 4
    @divibisan yes. In fact, there have been referenda like this already, in which Parliament passed legislation including clauses to the effect that "This law comes into force only if a confirmatory referendum is resolved in favour of it coming into force". This would mean they'd have to pass further legislation to repeal the then implemented prior law.
    – Dan Scally
    Nov 8, 2019 at 16:51

As the other answer described, referendums can be made "self-implementing": effectively a normal law which only comes into force if the referendum answer is in favor. Or a law could delegate implementation powers to a Minister.

But the big problem here is that a lot of Brexit promises were made on the basis of future agreement with the EU, and there is no way a UK referendum can bind the EU to a particular outcome. So "leave without a deal" and "leave with a specific deal" are viable options, but "leave with free market access and no freedom of movement" isn't.

  • No, but now that there is a specific deal, they could have a referendum on that deal
    – divibisan
    Nov 9, 2019 at 16:38

Parliament can make any law and/but it cannot bind itself. In that respect a referendum cannot be legally binding.

However, Parliament can make referendum law such that the Government is bound to act on the results or the result would be implemented without further legislation (because it is already provided for), and so on.

To avoid the effect of such a result, further legislation would be required from Parliament.

The House of Commons Library Briefing Paper for the-then European Union Referendum Bill 2015-16 gives us (the only) two nation-wide examples, in "contrast" with the EU Referendum legislation:

the legislation which provided for the referendum held on AV in May 2011 would have implemented the new system of voting without further legislation, provided that the boundary changes also provided for in the Parliamentary Voting System and Constituency Act 2011 were also implemented. In the event, there was a substantial majority against any change. The 1975 referendum [on EC membership] was held after the re-negotiated terms of the UK’s EC membership had been agreed by all EC Member States and the terms set out in a command paper and agreed by both Houses.

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