Sir Mark Sedwill: Britain’s top civil servant quits as Cabinet Secretary ahead of PM’s ‘Whitehall revolution’

BRITAIN'S most senior civil servant quit last night - and Boris Johnson is ready to replace him with a businessman in a radical Whitehall shake up. 

Sir Mark Sedwill stood down as Cabinet Secretary and National Security Adviser after increasingly frayed relations with the PM's inner circle. 

No 10 sources said Dominic Cummings thought Sedwill was a barrier to "Whitehall reform," with the agreement of Mr Johnson and Michael Gove, reports The Guardian.

His departure is part of an overhaul of the civil service spearheaded by No 10's top adviser Dominic Cummings.

Under the revamp Sir Mark's twin roles will be split apart.

Government sources said they could appoint an outsider such as "someone from the business world" to the Cabinet Secretary job.

The UK's chief Brexit negotiator David Frost will take the top security role from late August.

He will also stay on heading up the trade talks with Brussels until they finish.

Sir Mark said now was time to leave, having initially been drafted into the Cabinet Secretary job after the death of his predecessor Jeremy Heywood.

In a letter to the PM he wrote: "It was obviously right to stay on for the acute phase of the Covid-19 crisis.

"As you are setting out this week, the Government’s focus is now shifting to domestic and global recovery and renewal.”

He will now head up a new G7 panel on Global Economic Security and has been put forward for a life peerage.

Mr Johnson praised the outgoing civil service chief's career, paying tribute to his "unflappable good humour".

He said: "It has been by any standards a massive contribution - but as PM I have particularly appreciated your calm and shrewd advice.”

Sir Mark is said to have been increasingly "unhappy" following running battles with No 10's top team.

The PM reportedly came close to firing him at the end of last month, and his departure had been expected for some time.

Mr Cummings has vowed to overhaul the civil service, which he sees as a cosy club guilty of group think.

In a speech yesterday Cabinet Office minister Michael Gove said major change is needed.

He warned the "metropolitan" outlook of officials had contributed to governments becoming "estranged" from normal people.

The PM reportedly came close to firing him at the end of last month, and his departure had been expected for some time.