Mark Sedwill
The information relates to his past in Russia.
It comes after a searing article by former chancellor Philip Hammond about the PM.
“I would be sending Jeremy Corbyn in a cab to Buckingham Palace to say we’re taking over."
Labour leader warns of “anti-democratic abuse of power” in letter to Cabinet Secretary Sir Mark Sedwill.
The five things you need to know about politics today
The five things you need to know about politics today
Sir Mark Sedwill agrees "independent element" to his probe after "frank" meeting with Labour leader, party says.
Sir Mark Sedwill agrees "independent element" to his probe after "frank" meeting with Labour leader, party says.
Shadow chancellor hints ex-Mayor’s public views – and his private life – give cause for concern.
The warning comes after the Times newspaper carried quotes from unnamed civil servants about the Labour leader.