The uks top Civil Servant, sir mark sedwill, has confirmed he plans to stand down from the role in september. His exit follows reports of tensions between him and senior members of Boris Johnsons team. His other role as National Security adviser will be taken by mrjohnsons chief brexit adviser, david frost. In a letter to the Prime Minister, sir mark said, two years ago, when my predecessor fell ill, your predecessor asked me to step in as cabinet secretary, and you asked me to continue to support you through brexit and the election period. He went on. Im joined by lord odonnell, who was cabinet secretary and head of the Civil Service from 2005 2011. What do you make an announcement timing today . I think its very sad that mark is going, hes a great public servant, came in a very difficult time when my successor tragically and seriously ill and later died. Mark brought things together, he has lived through brexit and covid i9, its not been easy for him, and i know he will move on now t