Stamford MP Nick Boles said he will resign the Conservative whip if the Government pursues a no deal Brexit.
The Conservative MP for Grantham and Stamford said he accepted the Government ramping up preparations for a no deal to make sure the country is “ready for all eventualities”.
But he said if no deal became official government policy he would resign the whip and “vote in any way necessary to stop it from happening”.
The former minister, who has been championing a Norway-style Brexit, tweeted yesterday: “The Cabinet spent this morning discussing preparations for ‘no deal’ Brexit. I accept that it is prudent for the government to get ready for all eventualities. But I owe my constituents and my colleagues total clarity about my position.
“If at any point between now and 29 March the government were to announce that ‘no deal’ Brexit had become its policy, I would immediately resign the Conservative whip and vote in any way necessary to stop it from happening.
“Some have asked whether I am as opposed to a second referendum as I am to a ‘no deal’ Brexit. I am. We need to deliver Brexit, with a deal, on 29th March 2019. Nothing else will do.”
Meanwhile, Conservative Huntingdon MP Jonathan Djanogly has co-signed a cross-party letter sent to Theresa May which calls on her to agree a mechanism which would ensure a no deal Brexit could not take place.
The Prime Minister is currently trying to renegotiate her Brexit strategy after it was pulled earlier this month, a day before MPs were due to vote on it.
Mrs May admitted the deal did not have the support of the House of Commons.
MPs are now due to vote on the deal on the week beginning January 14.