Ex-Rutland and Melton MP Sir Alan Duncan served as minister for Europe and the Americas for three years until July 2019, leaving the Commons ahead of the last general election.
In the memoir, titled In The Thick of It, Duncan claims his former boss “despises” then-PM Theresa May and that he “seems to have embarked on a reckless journey into oblivion”.
“He is a clown, a self-centred ego, an embarrassing buffoon, with an untidy mind and sub-zero diplomatic judgement. He is an international stain on our reputation. He is a lonely, selfish, ill-disciplined, shambolic, shameless clot,” writes Duncan, in an extract from September 2017 shared in the Daily Mail on Saturday.
It isn’t the first time that Duncan has been critical of Johnson, telling the BBC’s Laura Kuennsberg that he was worried by the “fly by the seats of his pants, haphazard” nature of his colleague, fearing that he could go “smack into a crisis of government”.