It would be a “catastrophe” if Boris Johnson became Prime Minister, Alastair Campbell has said.
The former foreign secretary has said that he will run to be the next Conservative leader, after Theresa May announced she would resign on June 7.
Mr Campbell, the former press secretary of Downing Street, described Mr Johnson as a “lying hypocritical charlatan”.
Mr Johnson had described Mrs May’s speech as “dignified” despite previously saying he would not vote for her Brexit deal because the UK “can do better”.
He told talkRADIO’s Dan Wootton: “This guy is on the brink of becoming Prime Minister. I think that would be a catastrophe for our country and people need to wake up to that.
“It is hypocritical because he spent the whole time he was in government trying to undermine her.
“Now that she has finally gone, he has shed a few crocodile tears on her behalf.”
Mr Campbell added that he agrees “with civility in politics” but it would not stop him saying what he thought.
“I think I am more civil than some of the stuff that has been pumped around about Theresa May by her enemies,” he added.
“I do feel sorry for her on the level that she is a human being who has worked really hard to try and do something but she is the Prime Minister of our country and she has made so many mistakes.
“She made no effort to unify the country. She has showed very little empathy for the Windrush victims or for people sleeping rough on the streets.”
The other candidates confirmed to be running for Tory leadership include the current foreign secretary Jeremy Hunt and former work and pensions secretary Esther McVey.