Voting to leave: Article 50

If the UK votes to leave the EU the departure will not happen immediately: first comes a period when the UK can negotiate the details of its withdrawal from the EU, alongside its future relationship with the EU.

The process is regulated by Article 50 of the Treaty on European Union, as amended by the EU’s Lisbon Treaty. The withdrawal process starts with a notification from the Prime Minister to the European Council.  Then a negotiation begins, with the 27 continuing EU members on one side of the table and the UK on the other.

For a deal to be done, both sides need to agree. On the EU side, that requires support from a qualified majority of the continuing members and from the European Parliament. If no deal is done within two years of the notification, the UK’s membership automatically ceases, unless the UK and the 27 vote unanimously to extend negotiations.

Article 50 offers no mechanism to withdraw a notification of intent to leave. It is not clear whether this process applies only to the details of the UK’s withdrawal from the EU, or whether it also covers the UK’s future relationship with the EU. If it does not cover the latter issue, a separate negotiation, possibly with different rules, will be necessary.

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