The UK Food Standards Agency is to ramp up its campaign against shops that continue to sell a high proportion of chickens with Campylobacter, admitting that “much further work needs to be done.”

The bug makes 280,000 people ill each year, with 20,000 admitted to hospital.

Under proposals to be discussed this week, shoppers could be told to avoid certain supermarkets if they continue to sell high numbers of infected chickens in an explicit bid to change consumers’ “purchasing habits.”

The highly unusual intervention is likely to provoke legal challenges from retailers if it is forced through.

Officials will also consider whether the law should be changed to make it illegal to sell highly-contaminated poultry. Shops that fail to meet new requirements might be told to cook or freeze the infected chickens to kill the bacteria before the birds go on sale.

In a document outlining the proposals, Steve Wearne, director of policy at the FSA said: “The indications are that the prevalence of campylobacter in chickens is beginning to come down.