According to BBC News:
The Queen has given Royal Assent to the Brexit bill, clearing the way for Theresa May to start talks to leave the European Union.
The European Union (Notification of Withdrawal) Bill was passed by MPs and peers on Monday.
It allows the prime minister to notify Brussels that the UK is leaving the EU, with a two year process of exit negotiations to follow.
Mrs May says she will trigger the process by the end of the month.
It is unlikely to happen next week to avoid a clash with an informal summit of EU countries.