Supermarket chain Asda has been fined £300,000 for food safety breaches after inspectors found dead mice and flies at its north London home delivery depot.
Council officers found mouse droppings on the shelves and cereal and sugar packets gnawed by rodents during a visit to the Enfield site in May 2016.
Asda admitted three food safety and hygiene breaches at Highbury Corner Magistrates' Court in January.
It was fined on Friday and ordered to pay £4,843 in court costs.
The depot, in Southbury Road, distributes food to online customers across London and Essex.
"It beggars belief that a national retailer would allow food to be stored in an environment where rodents are running riot," said Daniel Anderson, Enfield Council's cabinet member for environment.
"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."
A spokesman for Asda said the depot had invested in and improved its pest management control.
He added: "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."