Tesco has been issued a warning by the competition watchdog after unlawfully blocking other supermarkets from opening shops near its stores.
The supermarket leaned on landlords to prevent them renting to rivals in 23 locations, according to the competition and markets authority (CMA).
The watchdog says Tesco"may have reduced competition" and left shoppers worse off by its actions.
After the initial discovery by the CMA, Tesco reviewed all of its land agreements and said it has now agreed to improve its internal processes and staff training to avoid future breaches.
The supermarket also said it would ensure that all new land agreements are in line with the order.
'It's unacceptable that Tesco had these unlawful restrictions'
Andrea Gomes da Silva, the CMA's executive director of markets and mergers, said: "It's unacceptable that Tesco had these unlawful restrictions in place for up to a decade.
"By making it harder for other supermarkets to open stores next to its branches, shoppers could have lost out.
"In the future, we want the ability to fine businesses if we find that they are in breach of our orders. That's why we've called on the Government for more powers."
Banning store openings is also unlawful under the Groceries Market Investigation (Controlled Land) Order 2010.
The locations where Tesco made breaches
Restrictive Covenants on land which Tesco has offered (or will offer) to remove:
• Victoria Street, Hednesford, Staffordshire
• Unit K Croft Retail Park, Bromborough, Merseyside
• Unit 5 West Durrington Centre, Worthing, West Sussex
Exclusivity arrangements which were not capped at five years (all relate to Tesco Express stores) each of which Tesco has offered to remove:
• Horton Retail Centre, Epsom, Surrey
• Great Suffolk Street, London,
• Mile End Road, London
• Oxford Road, Reading, Berkshire
• Chester Road, Northwich, Cheshire
• Rushey Green, London
• Wolseley Road, Plymouth
• Wellingborough Road, Northampton
• Pencoed, Mid-Glamorgan,
• Saxmunden Road, Aldeburgh, Sussex
• Askew Road, Shepherd’s Bush, London
• Fore Street, Edmonton, London
• Goodmayes Road, Rowallan, Dagenham
• Stainland Road, Halifax, West Yorkshire
• College Road, Harrow, London
• High Road, Kilburn, London
• Ladbroke Grove, London
• New Cavendish Street, London
• High Street, Penge, London
• Brentwood Road, Romford
