More than 250,000 people have signed a petition calling for a ban on cheaply produced low-quality food imports in post-Brexit trade deals. The National Farmers Union (NFU) is lobbying the government to ensure that imports from countries such as the US of food produced to lower standards than expected of UK farmers should not be allowed. Attempts last month to write a legal minimum standard into the agriculture bill failed, and the NFU has launched the petition to increase pressure on ministers. By Wednesday morning, 254,764 people had put their names to it. The petition says: “Farming throughout the UK has high standards of safety and welfare with an ambition to be net zero in greenhouse gas emissions by 2040. There are very strict controls on farming methods allowed in the UK and I expect the same of all food which is imported here so the food I eat is as safe, traceable and produced to high welfare and environmental standards. “Before the UK begins to negotiate trade deals with countries around the world, I call on the UK government to put into law rules that prevent food being imported to the UK which is produced in ways that would be illegal here.” Imports that are of particular concern to UK farmers and producers include US poultry products, such as chlorinated chicken and eggs, and hormone-injected beef. The TV chef Jamie Oliver issued a plea on social media for people to sign the petition, saying if there was no law to protect standards, the market would be flooded with very low quality, high salt and sugar products, and that trade deals allowing these imports would be “traumatic” to the British farming industry. The agriculture bill is moving to the House of Lords. Neil Parish, the chair of the environment food and rural affairs committee, who put forward one of the amendments to the bill in the Commons, said he hoped the Lords would amend the bill in order to protect against substandard imports in trade deals. A Defra spokesperson said: “We have been clear that in all of our trade negotiations – including with the US in our first round of negotiations – that we will not undermine our high domestic environmental protection, animal welfare and food safety standards by ensuring in any agreement British farmers are always able to compete.”