Prime Minister Theresa May’s Brexit talks with the Labour Party are a “grave mistake”, according to former defence secretary Gavin Williamson.
Mrs May is hoping to reach a cross-party consensus on her withdrawal agreement after failing to get it through Parliament three times.
He added Jeremy Corbyn’s only real interest was a general election.
BBC political correspondent Jonathan Blake said a Downing Street source had indicated Mr Williamson had been “supportive of the process while he was in the cabinet” and that he had “not been involved in the talks himself”.
The Conservative MP for South Staffordshire said doing a deal with Labour on Brexit “sounds so simple and so reasonable” – but would not work.
“Even if Labour do a deal, break bread with the prime minister and announce that both parties have reached an agreement, it can only ever end in tears,” he said.
“The Labour Party does not exist to help the Conservative Party.
“Jeremy Corbyn will do all he can to divide, disrupt and frustrate the Conservatives in the hope of bringing down the government.
“His goal, and he has made no secret of it, is to bring about a general election.”
Mr Williamson said the prime minister seemed oblivious to the fact many Tories believe she is “negotiating with the enemy”.
He continued: “Even if we get to a point where Jeremy Corbyn agrees a deal with the prime minister, when it comes to detailed scrutiny of the votes, Labour will revert to form.
“Even if it passes the first few votes, it will fail later.”
Mr Williamson’s comments come after Conservative MP Sir Graham Brady said that he expected the government’s Brexit talks with Labour to “peter out”within days.
Speaking on Saturday, the chairman of the 1922 Committee, said he found it “very hard” to see the talks leading to a “sensible resolution.”
Shadow health secretary Jon Ashworth said that Labour was acting “in good faith” in the negotiations but was “not getting very far”.
However, Education Secretary Damian Hinds told the BBC’s Andrew Marr programme that no other person in Mrs May’s position could change the “parliamentary reality” of needing to find a majority in the Commons.