British farmers “will go out of business” as a consequence of a trade deal with the United States, former environment secretary Theresa Villiers has warned.
Admitting that she had "great fears" about "unfettered competition between domestic farmers and US imports", she said it would be very difficult for domestic farmers to compete on price.
Ms Villiers, who left her Cabinet post in February’s reshuffle, said she was concerned about the impact of a deal on the rural economy and the union "because of the significance of livestock farming in Northern Ireland, Scotland and Wales".
International Trade Secretary Liz Truss has insisted that she would not do a trade deal with the US if it “does not benefit every sector of UK agriculture”.
However, opponents of practices such chlorine-washing chicken and hormone-injected beef fear farming standards may be bargained away in negotiations.
The Government is being urged to enshrine guarantees into the Agriculture Bill by the opposition benches and many of its own MPs.
Ms Villiers argued that an amendment to the bill would give certainty to farmers "that our negotiators wouldn't be able to give way” on standards.
Otherwise, she said the US negotiating team would "press very hard for the complete liberalisation of trade in food without any kind of preconditions".
She added: "We have legislated to prevent the importation of chicken that has been washed in chlorine or other substances, and I very much hope that stays on statute book.
“But I would imagine there will be significant pressure from the US to lift that restriction because they have had a longstanding dispute with the EU as to justification of that as a restriction."
Ms Truss and current Environment Secretary George Eustice are understood to have clashed over the issue, with the latter fearing cheap US products will threaten British farmers.
Minette Batters, the president of the National Farmers Union, said there may be only 60 days to save family farms.
“I have nothing against a UK-US trade deal as long as the imports into this country are produced to the same legal standards that we require from our farmers,” she said.
Beef farmer Dominic Harvey, 50, from Bampton, Devon, called on the Prime Minister to act.
He told the Daily Telegraph: “It would be a betrayal of British farmers if the Government signed off on a trade deal which floods the market with cheap, substandard meat.
“Boris Johnson needs to commit to enshrine food standards into law now to avoid a total decimation of the entire industry.”