Ex-Foreign Office chief says Boris Johnson was the 'worst' PM he worked under

The ex-top official at the Foreign Office who served under seven Prime Ministers has described Boris Johnson as the "worst" leader he worked for.

Sir Simon McDonald, whose explosive intervention helped to bring down Mr Johnson in the summer, said the former PM was "charismatic" but "chaotic".

As a civil servant for nearly four decades, he served under Margaret Thatcher, John Major, Tony Blair, Gordon Brown, David Cameron, Theresa May and Mr Johnson.