On March 13, the UK Parliament passed the European Union (Notification of Withdrawal) Bill (Bill). The Bill received Royal Assent on March 16.

During the course of debates on the Bill, the UK House of Lords had proposed two amendments, one relating to the rights of EU and European Economic Area (EEA) citizens legally resident in the United Kingdom, and the other to parliamentary approval on the final Brexit deal reached with the European Union. However, the UK House of Commons disagreed, and the Bill was passed back to the UK House of Lords with the amendments removed. The UK House of Lords did not insist on their amendments to the Bill, meaning that the Bill, as originally published, was adopted without changes.

It was expected that Prime Minister Theresa May would trigger the process to begin withdrawal negotiations with the European Union as soon as the Bill received Royal Assent. However, with the announcement by Nicola Sturgeon, First Minister of Scotland, that she will seek a second referendum on Scotland’s independence from the United Kingdom, the Prime Minister is expected to delay triggering Article 50 until the end of March.