The British Parliament approved the Withdrawal Agreement Act on 23 January 2020. On 24 January 2020, the President of the European Council and the President of the European Commission signed the agreement, which was approved by the European Parliament on 29 January. Finally, on 30 January, the Council adopted, by written procedure, the decision on the conclusion of the withdrawal agreement on behalf of the European Union.

The withdrawal agreement will enter into force upon the UK's exit from the EU, on 31 January 2020 at midnight CET. From that time on, the UK will no longer be an EU member state and will be considered as a third country.

A transitional period ending 31 December 2020 shall then begin and may be extended once for a maximum of one or two years, if agreed by the United Kingdom and the European Union before 1 July 2020.