Daniel Hannan, one of the leading Tory Brexiteers, has said there should be a second referendum if MPs vote to keep the UK in the customs union.
The MEP said if parliament forced Theresa May to abandon her plan for a so-called hard Brexit than it would leave the UK “plainly worse off than we are now”.
“Leaving the EU, but staying in the customs union, in other words putting Brussels in charge of 100% of our trade policy with 0% input that would be worse than we are now,” he told the BBC’s Daily Politics.
“In that situation I think you would need to have a new mandate either in the form of a general election or another referendum.”
Writing for ConservativeHome last week, Hannan acknowledged Brexit was “not working out” quite as he imagined it would.
“I had assumed that, by now, we’d have reached a broad national consensus around a moderate form of withdrawal that recognised the narrowness of the result,” he said.
The prime minister has ruled out holding a second referendum. Jeremy Corbyn has also said it is not Labour’s policy to back a second vote.
Shadow Chancellor John McDonell has said another Brexit referendum would cause divisions again and the “better route” is to have a general election.
Hannan’s intervention comes amid a fierce internal Cabinet battle over what the UK’s negotiation position on the customs union should be.
Health Secretary Jeremy Hunt this morning warned Boris Johnson that he was in danger of undermining Britain’s position in the Brexit negotiations.
The foreign secretary has branded plans for a “customs partnership” with the EU – thought to be May’s favoured option – “crazy”.
Hunt told BBC Radio 4′s Today programme: “If we are going to have these lively debates, we should have them in private because that will strengthen Theresa May’s negotiating hand.”
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Environment Secretary Michael Gove has also joined Johnson in publicly criticising the customs partnership option with the EU that would see the UK collect tariffs for Brussels.
The alternative model known as maximum facilitation, or “max fac”, would rely on new technology and trusted trader schemes.
With the top team divided, the prime minister’s former effective deputy, Damian Green, suggested Britain may have to stay in the current customs union longer than planned by extending the transition period in order to find a way forward – an idea arch Brexiteers have continually rejected.