A referendum is not the panacea it might seem

Remember, this is a purely legal argument and does not take into account any political consequences of ignoring the will of the people. However, for the moment, let us assume that the people voted to leave the EU. This would not trigger an application to Brussels under article 50 of the Lisbon Treaty. Under article 50(1) 'any member state may decide to withdraw from the [EU] in accordance with its own constitutional requirements.' This means that shortly after the result is known, parliament would have to vote on whether to make such an application to the EU. It would, thus, be theoretically possible for MPs to ignore the result of the referendum. Any tabled amendment would, too, be considered at this point, which might introduce a whole raft of alternatives, including the setting up of further negotiations before a final decision is made on whether to submit the application under article 50. Then we have the House of Lords. The net consequence is that we may never get to the point of making an application or, at best, it faces considerable delay.

Even if an application is made under article 50 by a reluctant government, the procedure for leaving the EU is complicated. Remember, we are in unchartered waters here. The framework for withdrawing from the EU is set out in article 218(3) of the Treaty on the Functioning of the European Union. Any agreement reached is subject to the qualified majority of the European council with the consent of the European parliament. In any event,treaties binding the UK and the EU will continue for two years after notification but, crucially, 'unless the European council, in agreement with the member state concerned, unanimously decides to extend this period'
article 50(3).

Depending on the terms of engagement agreed by parliament when authorising an article 50 application, the government may be in a position to agree an extension, possibly even to the point where any decision is put off until after the next general election. A new parliament, a new government, and a new mandate would allow the legislature to cancel any application under article 50. Even if we were to leave, a future parliament can vote to make an application under article 50(5) in the procedure referred to in article 49 to re-join the EU, exercising its sovereign right to do so over any referendum result.

So, a referendum is not the panacea it might seem within our constitution. The doctrine of parliamentary sovereignty, in an almost bizarre twist of events, may possibly prevent our withdrawal from the EU, even if the people decide otherwise.

Adrian Mason has spent 15 years in legal education specialising in civil litigation