“As we leave the European Union we will forge a bold new positive role for ourselves in the world, and we will make Britain a country that works not just for a privileged few but for every one of us,” Ms. May said, as her husband, Philip, stood nearby.

Another notable appointment was that of David Davis, a former minister for Europe and a longstanding Euroskeptic, to lead a new department responsible for exiting the European Union. Liam Fox, a former defense secretary, will take charge of international trade.