THERESA May has moved to take more personal control of the Brexit process with the appointment of a senior Whitehall official leading Britain's Brexit negotiating team to the role as her adviser on the European Union.

Oliver Robbins has been moved from Brexit Secretary David Davis's department to the advisory position in the Cabinet Office but will "continue to lead the official-side UK team" in negotiations, a UK Government spokesman said.

The move, coming amid the row over Foreign Secretary Boris Johnson’s intervention on Brexit, has occurred just days before the Prime Minister makes a major Brexit speech on Friday in Florence.

Philip Rycroft has been appointed as Mr Robbins' replacement as Permanent Secretary at the Department for Exiting the European Union.

The move follows reports of a rift between Mr Robbins and Mr Davis, who have led negotiations in Brussels.

Mr Robbins was second Permanent Secretary at the Home Office for a year during Mrs May's stint as Home Secretary.

Confirming his move, the Government spokesman said: "In order to strengthen cross-Government co-ordination of the next phase of negotiations with the European Union, the Prime Minister has appointed Oliver Robbins as her EU Adviser in the Cabinet Office, in addition to his role as EU Sherpa.

"He will continue to lead the official-side UK team in the negotiations, working closely with the Secretary of State for Exiting the European Union, and co-ordinate relations with the Commission and member states.

"The Prime Minister has appointed Philip Rycroft, currently Second Permanent Secretary at the Department for Exiting the EU and Cabinet Office, as Permanent Secretary, Department for Exiting the EU.

"The department will continue to support David Davis, the Secretary of State for Exiting the EU, to ensure a smooth exit and to seize the opportunities presented by leaving the EU.

"This will include his role as principal of the negotiations, leading on exit-related legislation, domestic preparedness for exit and engagement with stakeholders in the UK, including the devolved administrations, and in the EU27 and beyond,” she added.