Brexiters in the cabinet and other Conservative frontbenchers have privately told colleagues they are relaxed about the prospect of Britain crashing out of the EU on to World Trade Organisation rules, the Guardian understands.

Senior figures within the party have been persuaded by the argument that members of the WTO are less likely to try to punish the UK, while the European Union is looking to exact a political price for Brexit.

They now want to convince others that they should embrace the idea. “People are being told that WTO rules would be the end of the world. We need to explain to them why it isn’t,” said a senior government source. The foreign secretary, Boris Johnson, has also suggested the outcome would be “perfectly OK”.

But with opponents within the Conservative party who previously supported remaining in the EU branding the stance as “ideological baloney”, and even cabinet ministers expressing concerns, the issue looks set to be one of the most divisive facing Theresa May during the EU negotiations.

The tensions over the future trading relationship come as it was revealed that the EU would not hold its first Brexit summit until 29 April, a month after Theresa May triggers article 50 next week.

Donald Tusk, the president of the European council, announced that he would call a summit on the last Saturday in April to allow the EU’s 27 remaining members to agree on Brexit guidelines, a broad-brush outline of the political principles that will guide them through the next two years of negotiations.

May told a cabinet meeting on Tuesday that the triggering of article 50 would be a “historic event and will precipitate a shift in our role in the world and see Britain begin a bold new chapter as a prosperous, open and global nation”.

The issue of the future trading relationship is causing tensions behind the scenes, with some ministers said to be almost banging the drum for no deal.

A briefing by a senior WTO official in Westminster stressed that the Geneva-based organisation offered a different tone to Brussels, with “no undercurrent of tension [and it is] more pragmatic and commercial”. They claimed WTO rules would only pose challenges at the margins, and there need not be a “cliff edge [or] drama”.

The former cabinet member and Brexit supporter, Theresa Villiers, told the Guardian that it was in the best interests of the EU and the UK to secure a trade deal before the end of negotiations, but admitted it was not guaranteed. “If it isn’t possible, WTO rules would still allow us to do billions of pounds of business in goods and services with the EU,” she said, arguing the option was “by no means disastrous”.

But a source close to a cabinet minister disagreed, saying a number of senior figures were still warning of the impact of not having a deal. Others revealed that senior civil servants were still trying to persuade their political masters to keep open the prospect of a transitional deal, with some suggesting it could take five years after the 2019 Brexit date for a final trade deal to be hammered out.

Some Tory MPs believe that now the Brexit bill has become law, they face a major battle in preventing the government from caving into Eurosceptic backbenchers’ demands to walk away from the negotiating table without a deal.



They are alarmed that the idea of diverting to WTO trading terms is becoming widely talked about, and fear it is the preferred option for hardened Eurosceptics.



Bath MP Ben Howlett said: “Anyone that suggests that WTO would be a good thing is bonkers. This ideological baloney has to stop before we face an absolute disaster.”

Anna Soubry added: “There is nothing to be blase or relaxed about choosing for Britain to trade with our biggest economic partner under WTO rules. Every credible assessment done says this would be the worst trading arrangement possible for jobs, investment and growth.”

In the run-up to the referendum, Treasury research suggested reverting to WTO rules would knock between 5.4% and 9.5% off GDP after 15 years, and blow a £45bn hole in the public finances — though the basis of those forecasts was fiercely contested.



“Relying solely on the WTO rules would result in a significant reduction in the openness of the UK economy to the outside world,” it said. “It would be the alternative with the most negative long-term impact.”

But the campaign group Economists for Free Trade, which was known as Economists for Brexit during the referendum campaign, has been making the intellectual case for leaving the EU without a trade deal in place.



Labour’s shadow Brexit secretary, Keir Starmer, said the issue was likely to define the “ideological split” between the most ardent Brexiters and others. He said that the most vociferous out campaigners wanted a deregulated economy, without the EU’s social protections or rights.

“Under this view, not having a full collaborative and co-operative relationship with social Europe is a positive, not a risk,” he said.

The Liberal Democrat leader, Tim Farron, argued that WTO rules would be like “Britain falling into the abyss. But ministers, frankly, don’t seem to care.”

It comes as David Davis, the Brexit secretary, is due to appear before a Lords EU committee. Its chair, Lord Boswell, said that most people believed a reversion to WTO rules would have a significant impact.

He said his committee would push Davis on the process after article 50 is triggered. “We are interested in the nuts and bolts of the process, indications of the timescale, any indications of how that might work and interest in flow of information,” he said, insisting that parliament wanted to play a “constructive part rather than requiring a running commentary or micromanaging”.