Instead, she said she was “completely supportive of the prime minister” – without mentioning Chequers – adding: “I am fully 100 per cent behind the prime minister and we will get the best deal for this country.”
Ms McVey’s dodging of the question echoed the stance taken by Penny Mordaunt, the international development secretary, who has also refused to support the plan, already rejected by the EU.
And it came as the prime minister opened discussions with senior cabinet members, revealing some of the detail of her new proposals to break the deadlock over the Irish border.
The government is also seeking for the backstop to keep the entire UK in the EU’s customs territory, until technology provides a solution to avoid a hard Irish border.
The EU will insist the customs plan is not time-limited – which would anger Brexiteer ministers who fear it will become permanent, and could trigger further resignations.
When first floated in June, the issue was fudged. A paper said it “should be time-limited”, but that the UK only “expects” an alternative solution to be ready by the end of 2021.
It appeared that the “mini-cabinet” was not being asked to approve detailed proposals because UK officials had failed to make as much progress as hoped with their counterparts in Brussels.
Ms McVey was not one of the cabinet ministers invited to the meeting with the prime minister, prompting suggestions that potential troublemakers had been asked to stay away.
It was held as Ivan Rogers, the UK’s former ambassador to the EU, dismissed the chances of either the Chequers plan, or a looser Canada-style deal advocated by Brexiteers winning favour in Brussels.
Sir Ivan put the chances at “precisely zero”, adding: “The Johnsonian Canada-plus-plus is as big a pipe dream as Chequers. In some respects, rather bigger”
Meanwhile, Sir John Major criticised Tory MPs threatening the prime minister, arguing they were worse than the Eurosceptics that dogged his premiership.
“I have great sympathy for her plight and I think the way she is being treated by some of her colleagues is absolutely outrageous,” he told the BBC’s Political Thinking podcast.
Asked about the “bastards” from his era, he replied: “Their behaviour was pretty intolerable, but not nearly as intolerable as the way the present prime minister is being treated.”
One Conservative MP, Helen Grant, a party vice chairwoman, dismissed the DUP threat, insisting: “I think they’re bluffing.”