EU sources say Theresa May missed chance of swift start to Brexit negotiations, which are now likely to start in June

Theresa May has informed the European council that she will trigger article 50 on Wednesday 29 March, but European sources have made clear that Britain could be forced to wait until June to embark on formal talks. The Prime Minister's letter which officially notifies the European Council of the UK's intention to quit and will set in train a two-year negotiating process expected to lead to Britain leaving the EU on March 29, 2019. “We have always said we would trigger article 50 by the end of March and we thought it would be helpful to give advance notice.”

The prime minister’s spokesman said Barrow had a conversation with the office of the European council president, Donald Tusk, earlier on Monday to offer the EU notice of the date. The notification of triggering Article 50 of a key EU treaty will come in the form of a letter delivered to Tusk — though it was unclear whether it would come through an actual letter or an electronic missive.
British Prime Minister Theresa May announces that her government will trigger article 50, which begins the process of withdrawing from the European Union, on March 29.