Nonetheless, Johnson said he was "very confident" ahead of a meeting with European Commission President Jean-Claude Juncker on Monday. A source for Number 10 said Mr Johnson will make it clear he wants to secure a deal by October 18.
The premier is vowing to do everything he can to secure a divorce deal with the European Union and ratify it in Parliament before the deadline for leaving expires on October 31. He has been instructed by Parliament to seek a Brexit extension, which he says he will not do despite concerns that leaving without a deal would cause severe economic problems and possible food and medicine shortages.
Mr. Johnson has insisted that he wants a deal but he has refused to consider any delay, further antagonizing MPs including many fellow Conservatives.
Patel, now one of the frontline Cabinet ministers as United Kingdom home secretary, was a prominent Brexiteer and member of the Leave campaign, which was led by Johnson and Cabinet minister Michael Gove.
Johnson told the Mail on Sunday the United Kingdom will break out of the EU's "manacles" by the October 31 deadline like Bruce Banner, who transforms into the giant green Hulk.
In the English seaside resort of Southport, Mr Farage received a standing ovation from a 1,600-seat theatre packed with supporters, some of whom shouted out "traitor" when he named prominent politicians and media organisations who he said were trying to thwart Brexit.
Numerous rebels are on his own side and on Saturday night, one of his Conservative MPs defected to the pro-European Liberal Democrats. If the Supreme Court in London upholds that decision, Johnson could be forced to re-open the House of Commons.
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Former universities minister Sam Gyimah, who has called for a re-run of the 2016 Brexit referendum, condemned Johnson for "veering towards populism". He resigned immediately after the vote which saw 52 per cent of voters back leaving.
Cameron also reveals that during the Leave campaign, Johnson had privately raised the possibility of holding another referendum after fresh negotiations with the EU.
He said he "risked an outcome he didn't believe in because it would help his political career".
He also slammed Michael Gove, a Tory cabinet minister and former friend who co-lead the Vote Leave campaign with Mr. Johnson.
And he said Gove's claim that the public were exhausted of experts made him "an ambassador for the truth-twisting age of populism". May in July, Mr. Johnson has maintained that the backstop must be scrapped because it aligns the country too closely with the EU.
Raab argued that the EU's complaints about a lack of detail masked an unwillingness in Brussels to move on its own positions.
This is despite the Democratic Unionist Party - which supports the Conservatives in Parliament - having rejected any plan that would see Northern Ireland treated differently to the rest of the UK.
"The Hulk was a victor and was extremely popular and I'd rather be backing a character and a leader who is The Hulk, rather than one who is on the "chicken run", as Jeremy Corbyn is", Mr Barclay told Sky's Sophy Ridge On Sunday.