Trade Secretary Liam Fox has refused to rule out slashing all import tariffs after a no-deal Brexit.

The minister said “unilateral liberalisation” of tariffs was “a possibility” among “a range of options” for government should Britain crash out of the EU, while acknowledging the threat to jobs in farming and industry was “very clear”. 

It comes after HuffPost UK revealed he was considering a last-minute change to the Trade Bill which would allow the government to dramatically slash tariffs. 

The move – which could flood the market with cheap good and lead to mass job losses – was described by manufacturing union the GMB as potentially “the ultimate Brexit betrayal”. 

The news also prompted a series of warnings from sectors, including agriculture and ceramics, about the potentially devastating effect doing away with import duties would have. 

Fox, who campaigned for Leave, told MPs on the International Trade Committee “it is very clear to us what the risks would be” but said government would take a collective decision on the issue “shortly”.

But in a sign the cabinet could be split on the issue, Greg Clark, the business secretary, sounded a warning about the idea. 

He told MPs that zero tariffs on ceramics, for example, would expose the Leave-voting city of Stoke’s potteries industry to “aggressive” competition from China. 

“I want to see low tariffs but I want to make sure that we don’t ignore the importance of defending ourselves against dumping,” he told the Commons’ business committee. 

Clark added: “There are some industries, take ceramics for example, which I think has an important future as well as being important today, where there has been some very aggressive competition, dumping from China in particular, and we need to maintain the defences on that.” 

Fox went on to confirm he had identified “15,000 tariffs lines”, reductions on which would not have an impact on the UK. 

“There are areas where, if tariffs were to be reduced, it would not have an impact on the UK and would have a benefit to UK consumers,” he said. 

And when pressed over whether the EU might retaliate by varying tariffs, Fox replied: “I can’t see where reducing tariffs would be harmful.” 

While he said that “full liberalisation” of tariffs was a “possibility”, he acknowledged it would mean opening industry to “sudden competition” would leave the UK exposed. 

Fox also said under World Trade Organisation rules, the UK would have to apply tariffs to goods from the EU in the same way as those coming from the rest of the world.

“I have never advocated personally full liberalisation because of those very reasons. But that is a collective decision that has yet to be taken by the government,” he said.

“Representing a largely agricultural seat myself, I am very well aware of the impact that zero tariffs would have on our agricultural sector.

“Unilateral liberalisation is not what I would propose and I have not heard anyone else in government propose it.”

Committee chairman, SNP MP Angus MacNeil, told Fox: “There’s no hard and fast line [for] 3.2 million people, the 2.7 million in manufacturing, the half-a-million in farming, the 8,000 in ceramics. There’s nothing they can clutch to, there’s no security for them hold on to listening to you this morning.”