Theresa May says new key security adviser has ‘no proven expertise’ for the job

Theresa May has questioned why Boris Johnson picked a political appointee with "no proven expertise" as his new national security adviser (NSA).

The former prime minister pressed Cabinet Office minister Michael Gove to explain the decision to replace Sir Mark Sedwill with David Frost, currently Mr Johnson's chief EU negotiator.

Mr Johnson has been criticised for the appointment as, unlike previous holders of the post, Mr Frost is a political adviser rather than a career civil servant – who also lacks security experience.

Sir Mark is also stepping down as Cabinet Secretary and head of the Civil Service, amid reports of clashes with Mr Johnson's chief adviser Dominic Cummings.

Speaking during an urgent question in the Commons, Conservative MP Mrs May said: "I served on the National Security Council for nine years – six years as home secretary and three as prime minister.

"During that time, I listened to the expert independent advice from national security advisers.

"On Saturday (Mr Gove) said: 'We must be able to promote those with proven expertise.'

"Why then is the new national security adviser a political appointee with no proven expertise in national security?"

Mr Gove responded: "We have had previous national security advisers, all of them excellent, not all of them necessarily people who were steeped in the security world, some of whom were distinguished diplomats in their own right.

"David Frost is a distinguished diplomat in his own right, and it is entirely appropriate that the prime minister of the day should choose an adviser appropriate to the needs of the hour."