Sir Tim, Britain’s most senior diplomat in Brussels, will hand-deliver Theresa May’s historic Article 50 letter to the European Council president Donald Tusk during a day of highly stage-managed political theatre.

The era-defining document will already be in Belgium on Wednesday morning, and its all-important contents – Mrs May’s opening gambit for Brexit negotiations – will finally be released to the public within minutes of Mr Tusk receiving it at lunchtime.