The government has confirmed that on Wednesday 29 March 2017, the UK will give formal notification to the European Council of the UK’s intention to the leave the EU, under Article 50 of the Treaty on European Union. Theresa May is expected to make a statement to the House of Commons shortly afterwards.
Such notification will commence the 2-year period for negotiation of the UK’s exit treaty and new trade agreement with the EU. Subject to any transitional arrangements, or an extension to that period (by unanimous agreement of the remaining EU members), the UK’s membership of the EU will therefore cease by the end of March 2019. The precise date of Brexit day is a matter of interpretation of the wording of Article 50, which merely states that Brexit would occur “two years after the notification….[under Article 50]”. This suggests that Brexit day (day 1 of the UK’s new status as a non-EU member) could be either 29 or 30 March 2019. As Theresa May discovered to her cost in the Abu Qatada deportation case, it is important to pay attention to time limits in EU law.
The EU is expected to issue draft guidelines for the Brexit negotiations within 48 hours of the UK triggering Article 50.