The former Brexit secretary has warned Britain "will get its own Trump moment” if MPs vote to delay leaving the European Union.
David Davis said any move to extend Article 50 would be a “democratic disaster” and leave the Conservative Party “massively damaged”.
He told the BBC’s Andrew Marr Show: “It would absolutely undermine belief in democracy in this country and certainly belief in the establishment political parties.
“Britain will get its Trump moment.
“The British people who voted for this – and a large number of Remainers who didn’t vote for it but still think it should be carried through because they believe in democracy – will see a government, a parliament, walking away from a question that they themselves put to the people.”
On Tuesday, the Prime Minister will again ask MPs to back her Brexit deal, but if they reject it they may get a chance to vote to delay Brexit.
Mr Davis added: “The House will have to choose between something that might have a risk of some short-term but manageable economic turbulence or something which for certain would be a democratic disaster – namely not delivering on the referendum.”
He said if they did not deliver it could leave big parties such as the Tories and Labour vulnerable in future elections.
“The British people would say: ‘We want to teach you a lesson.’”
The UK is due to leave the EU on March 29.
Mr Davis resigned from government in July because he did not believe in Theresa May’s Brexit plan.
His warning came after Brexiteer Tories and their DUP allies warned the Government was heading for an "inevitable" defeat on Tuesday unless it can secure last minute concessions from the EU on the Northern Ireland backstop.
The UK is still locked in negotiations with the European Union in Brussels.
