Tories are believed to be preparing to sign letters demanding a vote of no confidence in May's authority, to try and take the total closer to the 48 MPs required to trigger a leadership contest. The prime minister is hoping to impose order at the meeting of the Brexit sub-committee, charged with mapping out the way forward in negotiations with theEuropean Union (EU).
MPs on either side of the divide over a so-called hard Brexit, which foresees the UK leaving the EU by breaking all past links with the economic bloc, have been clashing against each other on May's leadership.
"I remain a strong backer of the prime minister. I've been very disappointed to see the soundings off. I think they need to stop and I think people need to get behind her," she said.
Downing Street was also forced to respond to critics, claiming that May was "grasping the many opportunities" of Brexit well.
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"How long has the prime minister got? I am of the view that any sort of change in leadership is not helpful at the moment and I dont support that, but I do think the window is closing because politics can be quite a brutal game," he said.
The infighting has intensified as more and more pro- Brexit MPs want UK Chancellor Philip Hammond to be sacked by the prime minister over his call for an ultra-soft Brexit.
Downing Street has dismissed calls for his sacking, as the Brexit debate gets focused on the so-called transition period planned for immediately after March 29, 2019 the official date of Britains exit from the union.