Amid mounting concerns that East Anglian farmers could be undercut by cheap post-Brexit food imports, a Norfolk MP said US trade offered “huge opportunity for all farmers”.

International trade secretary Elizabeth Truss, who also represents South West Norfolk, promised that food standards would not be undermined in the drive for an increased movement of products across the Atlantic.

Farmers fear that, unless legal safeguards are put in place, the UK could be flooded with cheap imports produced to lower environmental, animal welfare and food safety standards than are required in the UK.

Those concerns deepened this week when an amendment aiming to guarantee all food imports had to meet the UK’s high standards was defeated during a debate on the Agriculture Bill.

Meanwhile, reports surfaced that the government is drawing up plans to cut tariffs on US agricultural imports as part of a “big concession package” to help the progress of trade negotiations, prompting more angry reactions from farmers demanding more than “verbal assurances” from ministers to protect their industry.

Ms Truss said the government “will never undermine our high domestic environmental protection, animal welfare and food safety standards – ensuring that in any agreement British farmers are always able to compete”.

READ MORE: MPs ‘missed opportunity’ to secure vital safeguards for food standards, say farmersShe told Farmers’ Weekly that exporters of products including beef and lamb could benefit from huge market opportunities if the US lifted import tariffs, but she would be “extremely cautious to ensure any ‘opening up’ does not cause an unwanted downturn for domestic producers”.

“Our analysis shows that agricultural sectors are set to gain from a US deal,” she said.

“An agreement with the US could remove tariffs of up to 26pc on British beef – a market only recently opened and worth £66m to UK farmers.

“A deal with the US could bring similar benefits for the lamb industry. It is not widely known that the US is the second-largest importer of lamb in the world, and even a 3pc market share could boost annual UK lamb exports by £18m.

“We will always ensure that UK free-trade agreements (FTAs) are fair and reciprocal. British farmers will not face unbalanced competition. No UK import standards will be diminished as part of an FTA.

“This is a huge opportunity for all farmers, wherever they are in the UK.”

Nick von Westerholz, director of EU Exit and international trade for the National Farmers’ Union (NFU), said verbal assurances were not enough, and farmers wanted to know precisely how the government will achieve its commitments on standards “in law and in practice” while lowering barriers for agricultural imports.

“The issue simply hasn’t been resolved,” he said. “It isn’t plausible to say on one hand ‘we won’t allow in food produced to lower standards’, while pursuing quick trade deals and tariff liberalisation on the other.”