The National Farmers’ Union has become embroiled in a row with the Government over chlorinated chicken as its president used its New Year message to warn ministers not to “betray” producers in any post-Brexit trade deals.

Minette Batters, president of the NFU, said UK farmers had worked hard to achieve some of the “highest standards of animal welfare, environmental protection and food safety in the world” and warned that this would be undermined if food stuffs such as chlorinated chicken and hormone-fed beef were sold in British stores post-Brexit.

“We cannot risk betraying these values by allowing food imports such as chlorinated chicken and hormone-fed beef - food that has been produced in ways that are illegal here - on to our supermarket shelves," she said.

In the US it is common practice to sterilise chicken carcasses with chlorine to counteract high infection rates of salmonella and listeria, as well as feeding growth hormones to cattle.

Woody Johnson, the US Ambassador to Britain, has previously urged the UK to embrace American farming methods in order to secure a transatlantic trade deal, while Boris Johnson highlighted earlier this year that the chlorine washing of chicken was the same process EU farmers used to treat fruit and vegetables. The Prime Minister said it was an effective way of treating “potentially lethal” bacteria.

However a spokesman for the Government said it would “always back Britain’s farmers and make sure they can seize the opportunities presented by Brexit” and would not “compromise” on the high environmental and animal welfare standards the UK has achieved, once it leaves the EU.