Supermarket chain Asda has been fined £300,000 for food safety failings after inspectors found dead mice and flies at a home delivery depot.
Council safety officers made the discovery in the bread section at the site in Enfield, which distributes food to online shoppers in London and Essex.
They also found mouse droppings on shelves and in a packet of cereal, while a pack of sugar in the home baking aisle had been gnawed by rodents.
Inspectors also found the shells of fly pupae under shelves, spilt foodstuffs and rotting coriander in home delivery trays when they visited the Southbury Road depot on May 27 last year.
Asda was fined on Friday and ordered to pay £4,843 costs after it admitted three food safety and hygiene breaches at Highbury Corner Magistrates' Court in January, Enfield Council said.
Daniel Anderson, the cabinet member for environment, said: "It beggars belief that a national retailer would allow food to be stored in an environment where rodents are running riot.
"It is simply unacceptable for customers to be exposed to the potential risk of harm because a company cannot get its house in order and store foodstuff in a safe and hygienic manner.
"Hopefully (the fine) will send out a strong message to all retailers that we will not tolerate them being less than properly vigilant and ensuring their staff abide by their own stated hygiene policies to protect the health and well-being of their customers."
Asda said it had carried out a "full and thorough review" to improve its food safety processes, including its pest control.
A spokesman for the supermarket said: "The conditions found at our Enfield home shopping centre in May 2016 were completely unacceptable and we are deeply sorry that on this occasion the strict processes we have in place failed at a local level.
"We would like to reassure all our customers that immediate steps were taken as soon as the issue was flagged last year to restore the high standards that our customers expect from us."