One of Theresa May's closest allies has accused the prime minister of trying to "blackmail" MPs into backing her Chequers plan, which he says is "dead as a dodo".
Sir Mike Penning, a former minister who worked under Mrs May at the Home Office and backed her Conservative leadership campaign, said moderate MPs will not back her plan and she needs to "wake up and smell the coffee" and realise the numbers "don't stack up" to get Chequers through the House of Commons.
In an interview with The Telegraph, Sir Mike said Mrs May is playing “Russian Roulette” with the country and treating her own MPs “like children who belong on the naughty step”.
The MP for Hemel Hempstead, who was knighted last year, told ITV News he made the intervention as Mrs May meets with EU leaders in Salzburg because "she had to know just how upset we are and that we will not accept Chequers".
"She needs to use what we're saying as a weapon, a negotiating weapon, with the rest of the European Union to get much better than Chequers because if she comes back with Chequers it is as dead as a dodo," Sir Mike said.
He said the Chequers plan, agreed by the Cabinet in July, does not fulfill the commitments of the Brexit referendum and that suggesting the only options were Chequers or no deal was like "attempting to blackmail loyal members like myself, people who are sticking up for their constituents".
There is growing speculation about Mrs May's future, especially if she is forced to back down over Chequers.
But former soldier Sir Mike, who said he was joining the hardline Brexiteer European Research Group, said switching leader would be the wrong move.
He told ITV News: "To change leader in the middle of a negotiation is a very foolish thing to do, no one is going to do that.
"But she needs to have the strength and backbone that I know that she has."
With a deal yet to be agreed, the prime minister has insisted the UK’s March 29 2019 departure from the European Union will not be delayed.