AMBER Rudd has set a large Brexit hare running by raising the possibility that the UK Government could opt to stay in the European Customs Union, contrary to current policy.

At a Westminster lunch for parliamentary journalists, taking place as MPs were debating the issue of Britain remaining in the customs union, the Home Secretary was asked if it was more or less likely the UK would stay in it, to which Ms Rudd replied: “I’m afraid I’m not going to be drawn on that at the moment.

“We still have a few discussions to be had in a really positive, consensual, easy way amongst some of my Cabinet colleagues in order to arrive at a final position.”

READ MORE: Amber Rudd faces fresh calls to resign over migrant removal targets

Ms Rudd’s words will enrage Brexiteers, not least among her Cabinet colleagues given suggestions Boris Johnson, the Foreign Secretary, has made it clear to friends he would resign if this ever became Government policy.

Theresa May has, as was the case yesterday, repeatedly insisted the UK post Brexit will leave the customs union, so that the country can make trade deals across the globe.

Labour’s Sir Keir Starmer, commenting on the Home Secretary’s remarks, said: “Amber Rudd appears to have let slip that discussions around the Cabinet table about negotiating a customs union with the EU have not in fact concluded.

“If that is so, then the Prime Minister should rethink her approach and listen to the growing chorus of voices in Parliament and in business that believe she has got it wrong on a customs union,” he added.

READ MORE: Amber Rudd faces fresh calls to resign over migrant removal targets

t the weekend, there were reports the Prime Minister’s team had privately conceded that she could have to accept permanent membership of a European customs union, after a secret wargaming exercise concluded leading Brexit supporters such as David Davis and Michael Gove would not resign in protest.

At a meeting of Mrs May's political team last month, it was suggested the PM and her senior aides would “not be crying into our beer" if Westminster forced the Government's hand.

A few days ago, the House of Lords voted to stay in a customs union. It is expected that this will be replicated in today’s non-binding vote in the Commons.

READ MORE: Amber Rudd faces fresh calls to resign over migrant removal targets

The crunch is likely to come when MPs vote in the next few weeks on an amendment to keeping Britain in the customs union; as many as 10 Tory MPs could rebel and overturn Mrs May's majority.

The Democratic Unionists, whose 10 MPs provide the PM with her Commons majority, have made it clear they would collapse the Government if there was any sign it was prepared to take Northern Ireland back into a customs union with the EU.