Theresa May has been warned the Conservative Party’s Brexit approach risks creating a generation-long backlash, as MPs secured a symbolic customs union victory.
Nicky Morgan and Ken Clarke were among the senior pro-EU Tories who urged the Prime Minister to retain the option of a customs union between the UK and EU, amid concerns over the impact of major changes to peace in Northern Ireland.
Former education secretary Mrs Morgan advised her party that they “will not be forgiven for a generation” if they ignore the “evidence for peace” in Northern Ireland and undermine business and financial security.
Mr Clarke argued the UK would suffer “terrible damage” if customs union arrangements were not replicated while Tory former attorney general Dominic Grieve said the UK is behaving in the “most extraordinary and blinded fashion as we blunder around ignoring the realities”.
Mr Grieve cited warnings from Japan that every Japanese company will leave Britain within a decade if they could not trade freely with Europe.
But very few Brexit-backing MPs attended the debate, which emerged after 10 select committee chairs moved a motion on the issue.
Speaking during the debate, Treasury Select Committee chairwoman Mrs Morgan said: “This country has been asked to experiment at other people’s pleasure with a free trade policy where we do not know what the costs will be for constituents and businesses in this country.
“And I say to my party: If we undermine and ignore the evidence for peace in Northern Ireland and we undermine the business and financial security of the people in this country we will not be forgiven for a generation.”
Mr Clarke earlier said former colleagues in the governments of Margaret Thatcher and Sir John Major who now sit as peers all backed the motion, adding it would be “grossly irresponsible” to put a hard border in the middle of Ireland.
He went on: “What we want is no new barriers. What we want is no customs processes. What we want is the necessary level of regulatory convergence. I think the easy way to do it is to stay in the customs union and stay in the single market.
“If not, we need what the Prime Minister described as a customs partnership – something which looks remarkably like the single market and customs union.
“It would do terrible damage to this country if, for strange ideological reasons in the confused aftermath to a misguided referendum, if we were to take such a foolish step as not to replicate it in any future arrangements we have.”
Independent North Down MP Lady Hermon warned Mrs May over the prospects of a “no-deal” Brexit for the Irish border, telling the debate: “If we have no deal we will inevitably have a hard border in Northern Ireland and we would see the return of violence in Northern Ireland.”
But Labour Brexiteer and former minister Kate Hoey said the EU was “seizing on divisions” in the Commons to pursue demands.
She said: “I do believe that the European Union is actually seizing on divisions on this issue to pursue certain demands which are just not necessary.
“It’s certainly using the Irish border as an issue in terms of the customs union.”
Conservative MP Matt Warman (Boston and Skegness) told his fellow Tories that “democracy must come first” as he urged them to respect the referendum result.
Leading Tory remainer Anna Soubry was “talked of frequently” in his Boston constituency, he said, adding: “I know that she does not seek to undermine democracy. I know that she of all people is a democrat.
“But the impression that is given outside this place is too often that people do not trust the result and they do not trust people out there in this country to have made a decision.”
Mr Warman went on to say: “I would say gently to my own colleagues, democracy must come first.”
Treasury minister Mel Stride, responding for the Government, said they were “committed” to no hard border between Northern Ireland and the Republic.
He added: “Moving forward, we will seek to maximise our trade across all countries and markets as we prepare for the challenges and the exciting opportunities ahead – confident as an independent trading nation, proud of our long history as a global champion of free trade.”
Commons Speaker John Bercow said there was “compelling logic” for the Government to respond to the debate within three months, as with opposition day debates, and said it would also be a “courtesy” for the Government to give an explanation to the House.