Britain's Prime Minister Theresa May listens to the Emir of Qatar Sheikh Tamim bin Hamad al-Thani at the start of their meeting at 10 Downing Street, London, Britain July 24, 2018. (Photo/Agencies)

British Prime minister Theresa May said on Tuesday she would now lead the country in negotiations with the European Union, shifting the focus of the Brexit department towards preparing for Britain's departure from the bloc.

A special unit within May's office has played an increasing role in Brexit talks during recent months, and Tuesday's announcement formalises that shift in responsibility.

"I will lead the negotiations with the European Union, with the Secretary of State for Exiting the European Union deputising on my behalf," May said in a written statement to parliament.

"DExEU (Department for Exiting the EU) will continue to lead on all of the government's preparations for Brexit: domestic preparations in both a deal and a no deal scenario, all of the necessary legislation, and preparations for the negotiations to implement the detail of the Future Framework."