Sir Timothy Earle Barrow is a British diplomat who served as Permanent Representative of the United Kingdom to the European Union from 2017 to 2020 and as the British Ambassador to the European Union from 2020 to 2021. He currently serves as National Security Adviser.
Barrow was appointed as Permanent Representative in January 2017 following the resignation of his predecessor, Ivan Rogers, and played an important role in the United Kingdom Brexit negotiations. He was responsible on 29 March 2017 for formally invoking Article 50 of the Treaty on the European Union on behalf of the UK. When the United Kingdom left the EU on 31 January 2020, Barrow became HM Ambassador to the European Union.
Barrow has been a civil servant in the Foreign and Commonwealth Office (FCO) since 1986. He served in London, Kyiv, Moscow and Brussels before his appointment as the British Ambassador to Ukraine in 2006. In 2008, he became the Ambassador to the Western European Union and the UK Representative to the Political and Security Committee. From 2011 to 2016, he served as the British Ambassador to Russia before returning to London as the FCDO's Political Director, the number two in the department to the Permanent Under-Secretary of State for Foreign Affairs.