Brexit D-Day: What happens now? York legal eagle answers four crucial questions

What will change when Article 50 is triggered?

It is like handing in your resignation, but with a longer notice period. Notifying the European Council of the UK’s intention to leave the EU does not result in immediate changes; EU law will continue to apply, but the notification binds us to leaving, and starts the countdown clock.

The EU treaties ‘shall cease to apply’ (ie the UK will cease to be a Member State) two years after notification.

According to Article 50 it could happen in less than two years, if a withdrawal agreement is concluded and enters into force before then. But given the scale of the task ahead, and the UK’s shortage of negotiators, coming in under the two-year deadline seems unlikely.

Will EU laws cease to apply after the two years are up?

The EU treaties will cease to apply, but much of EU law is implemented into national laws, which will continue to apply unless and until amended or repealed.

We will have to wait for the Great Repeal Bill to get more of an idea of what the government has in mind.

In short, EU laws implemented in primary laws can only be changed by Parliament, and both Houses must oversee such changes.

But a lot of EU-based rights are contained in secondary law, over which the government has considerably more control.

Can the UK withdraw its Article 50 notification?

This is possibly the key question – once the withdrawal process has been set in motion, is it possible to stop it before the two years are up, for any reason or change of circumstances?

Article 50 does not tell us. In the Miller case (about parliament having a say on the triggering of Article 50) both parties agreed, for strategic reasons, that notification started an irreversible process.

But much depends on what the other 27 Member States think. If the UK sought to stop the process, and met with any opposition among the other states, then we may have to ask the Court of Justice of the European Union to decide on the reversibility of Article 50.

Can the two years be extended?

To employ a favoured legal answer, ‘it depends’. Yes, extension is possible, but the UK would need to get unanimous agreement from the members of the European Council – ie the heads of state/government of the other 27 Member States.

This may depend on how well disposed the other states are to the UK after a long period of negotiation.

Also, if reaching that agreement is likely to take a long time, then meta-negotiations about an extension to negotiations would have to commence well before the two year period is up.