In this June 6, 2018 file photo, Britain's Secretary of State for Exiting the European Union David Davis delivers a speech in London, on Britain's vision for the future security relationship with the EU. British media outlets say the most senior official in charge of negotiating Britain's exit from the European Union has quit Prime Minister Theresa May's government. The Press Association news agency, the BBC and others say Davis resigned Sunday, July 8, 48 hours after May announced that her divided government had at last agreed on a plan for ties with the EU after the U.K. leaves next year. (Leon Neal/Pool Photo via AP, File)
LONDON — Britain’s most senior official in charge of negotiating the country’s exit from the European Union resigned Sunday, two days after Prime Minister Theresa May announced she had finally united her quarrelsome government behind a plan for Brexit.