Welwyn Garden City-based Tesco has today been ordered to pay more than £8m in fines and costs after pleading guilty at Preston Crown Court to a pollution incident.
Between 2 and 3 July 2014 approximately 23,500 litres (5,169 gallons) of petrol escaped from a station filling tank in Haslingden, Lancashire.
The Environment Agency's joint investigation with partners found the incident resulted from Tesco's failure to address a known issue with part of the fuel delivery system. There was also an inadequate alarm system and poor emergency procedures, the agency said.
A Tesco spokesperson said: "We sincerely regret the fuel spillage incident at our petrol station in Haslingden and we're sorry for the impact it had on the local environment, our customers and the community.
"This was a deeply unfortunate isolated incident and one for which we have taken full responsibility.
"Following the incident, we have inspected all relevant petrol stations, introduced a new real-time monitoring system and made a number of further improvements to protect against similar incidents happening again."