THERESA May has said her Conservative Party remains “united” behind her, despite yet more public division between Cabinet members and senior party figures.

Speaking during a television interview and ahead of the Conservative Party conference, which began yesterday, the Prime Minister insisted that Boris Johnson was “absolutely behind” her Brexit plans.

Her comments followed yet another outburst from the Foreign Secretary in which he outlined his four “red lines” for Brexit negotiations.

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Johnson, who is believed to be harbouring leadership ambitions, opened up divisions once more during an interview on Saturday in which he said that he did not want the UK to stay within the EU “a second longer” than the two-year transition period, due to begin in March 2019.

He added that Leave voters were being betrayed and warned against further compromises on the issue.

“Am I impatient about it, do I want to get it done as fast as possible? Yes, absolutely,” he said. “Do I want the delay to go on longer than two years? Not a second more.”

Johnson went on to list the other three red lines: the UK must refuse to accept any new EU rulings, there must be no payment made to access the single market, and there must be a commitment to not shadowing EU rules in order to gain access to the single market.

Then in an awkward interview yesterday morning the Prime Minister claimed that Johnson was behind the stance set out in her Florence speech the previous week.

When May was asked if she had lost authority over her ministerial team, May responded that the Cabinet was “united in a mission to build a country that works for everyone and agreed on the approach that we take in Florence”.

“Boris is absolutely behind the Florence speech and the line that we have taken,” she added. “What Boris is saying is the importance of the approach we have taken in the Florence speech. That has moved the discussion on and created a momentum in the negotiations.”

When asked if Johnson was “unsackable”, May replied: “Let’s be very clear about what we have here in this government. We have a government that is determined to build a country that works for everyone.”

Later in the day former party chairman Grant Shapps said that May cannot sack Johnson “for the simple reason that her majority is so small that her position is not strong enough”.

Then, in an interview on a Scottish political show, Scottish Conservatives leader Ruth Davidson dodged a question about Johnson, on whether or not he was immune to criticism.

After accusing a newspaper of “making mischief” between her and Johnson, and accusing the same publication of creating divisions where there are none, she added that it was not a problem that Johnson was “empowered to talk about the area under which their department operates”.

Other Tory MPs were less forgiving in their response.

Remain-backing MP Anna Soubry said on Twitter: “People are fed up with Tory wars and Brexit mixed messages. Boris Johnson must grow up or go.”

The most damaging criticism, however, was dished out by Tory peer Michael Heseltine who slammed Johnson’s “phoney” and “duplicitous” arguments and questioned his future as a Cabinet Secretary, adding that “we all know what he’s up to”.

“I understand those arguments but they are phony, they are duplicitous,” he said.

“Talking about a world hungry for new British exporters to suddenly come over the horizon is just talking about something that doesn’t exist.”