Boris Johnson, one of Britain's most prominent Brexit campaigners, said Prime Minister Theresa May's party had lost its confidence and called on Conservatives to champion the free market to keep the opposition Labour Party out of power.
Boris Johnson drew huge crowds at his speech at the party conference, as he attacked Theresa May's Brexit plan.
Mr Johnson made no open suggestion he would challenge Ms May, saying the party must back one of her earlier Brexit plans which he says she has ditched, and said one of the few predictions the Treasury department had got right was that he would not be prime minister.
Speaking at a fringe meeting hosted by the ConservativeHome website, Mr Johnson will say: "We must on no account follow Corbyn, and start to treat capitalism as a kind of boo word".
But he warned: 'If we cheat the electorate - and Chequers is a cheat - we will escalate the sense of mistrust.
"We will not trample on our project to rescue a party that is deeply divided and apparently not capable, of course, a common line to exit the mess of Brexit".
Several newspapers reported on Tuesday morning that the Scottish Conservatives would strongly oppose any attempt by Mr Johnson to replace Theresa May as prime minister.
Mr Johnson said that Mrs May's Chequers blueprint - which ties Britain to a common rulebook with the EU for trade in goods - would be "politically humiliating for a £2 trillion economy" and would subject the United Kingdom to European directives and rules.
Man missing after plane plunges into sea in Micronesia
What caused the crash and the exact sequence of events remains unclear. "I thought "this is not the way it's supposed to happen". The airline did not immediately offer any other details about the passenger, such as his age or nationality.
Mr Johnson will also use his speech to issue a clarion call to activists to "believe in Conservative values".
In her crucial conference speech, the PM will make a direct appeal to mainstream Labour voters disillusioned by Jeremy Corbyn's left-wing agenda to switch to the "decent, moderate, patriotic" Tories.
Questioned again later on BBC Radio 4's Today about how she felt that her former colleague appeared to be mocking her, she replied: "What I feel is that I, and this government, and this party, are getting on with the important job. of getting a good deal for the United Kingdom when we leave the European Union".
Duddridge's letter is the latest sign of rebellion against May, who has faced constant attacks from hard-Brexiteer MPs - including Johnson and Jacob Rees-Mogg - over her plans for leaving the EU.
And he added: "The Prime Minister seems incapable of doing this".
"We can not, must not and will not let this weaselly cabal of superannuated Marxists and Hugo Chavez-admiring, anti-semitism-condoning Kremlin apologists anywhere near the government of this country".
"We have a very, very strong leader in Scotland in Ruth Davidson who had a very significant contribution to make to this conference".
He added: "I don't think this is a time to be talking about leadership challenges, it is a time to be supporting our Prime Minister as she takes forward this incredibly hard task of getting a deal with the European Union". May's plan during a speech to around 1,500 party members.