A Paddington supermarket was closed last night because of a serious mouse infestation.
Somerfield, in Edgware Road, was shut after an inspection by environmental health inspectors revealed the supermarket was infested with mice.
They visited the store following a complaint from a member of the public.
Westminster Council's operations manager for food, health and safety Richard Block said: "Mice carry and spread a number of serious diseases so we have to take tough action whenever and wherever we find them posing a risk to health. We're now investigating this incident at Somerfield."
A Somerfield spokeswoman said: "As a responsible food retailer, our stores have regular stringent checks by pest control companies and this is a one off incident that has been dealt with quickly and efficiently by our in-house health and safety team.
"We are working together with the Environmental Health department to eradicate the problem and we hope to reopen the store later today.
"We apologise for any inconvenience caused to shoppers and we remain vigilant about standards of cleanliness and hygiene in our stores."