The Prime Minister was booed by her own Ministers at the Conservatives Party Conference at a two-hour grassroots event, amid rumours there is a building mutiny.
She was also denied a standing ovation as she left the closed meeting of the National Conservative Convention (NCC).
This is the most senior body of the party’s voluntary wing and the event kicks off the conference every year.
Attendee John Stafford told the Daily Telegraph it was a “wave of grumbling”.
He added: “The party leader normally gets a standing ovation… but Mrs May just walked off and that was it.
“This is my 55th party conference and I’ve never seen that.”
Another person claimed: “There was a boo when she mentioned Chequers. It was a bit embarrassing.”
Head of the grassroots movement the Conservative Campaign for Democracy, John Stafford, gave a speech which said the Prime Minister would be seen as a “dictator” if she didn’t abandon Chequers.
Speaking at a fringe meeting, he said: “If the Prime Minister pursues her goal of the Chequers agreement in the face of the 17 million who voted to leave the European Union, in the face of a large number of her members of parliament, in the face of a sizeable majority of party members, then she will be showing all the characteristics of a dictator. If it looks like a duck, quacks like a duck, walks like a duck, it is a duck!”
A senior Tory MP claimed: “Eden wasn’t booed after Suez. Iain Duncan-Smith was given 19 standing ovations just weeks before he lost a vote of no confidence.
“Even John Major wasn’t booed during Maastricht. For Mrs May to be booed over Chequers is unprecedented.”
The humiliating claims came as a former Brexit Minister claimed Mrs May’s plans are causing eurosceptics “considerable alarm”.
Steve Baker claimed US officials “despair” of Chequers as it leaves the UK a “satellite of the EU”.
He said the proposals, which share a “common rulebook” with Brussels” on some goods exports “takes off the table all of the benefits of an independent trade and regulatory policy”.
It has also been reported that Mrs May is preparing to compromise even further with the EU.
The Times claims the Prime Minister is preparing a “grand bargain” offer to Brussels.
This would involve the UK still retaining EU customs rules on goods after a transition period ends in December 2020.
It could potentially mean the UK would not be able to strike trade deals for many years.
What’s more, the “temporary” arrangement will have no time limit and end only when a technological solution to the Irish border issue was found.
A spokesman for the Prime Minister denied she was booed and said the meeting was “warm and constructive”.