Police have warned Black Friday online shoppers to change their passwords after a man was arrested for alleged cyber offences against Tesco.
The 28-year-old was arrested in Middlesbrough after the supermarket found someone was trying to breach its online system.
No customer details, financial or personal were obtained in the alleged incident, Tesco said.
The Metropolitan Police is now urging shoppers to be vigilant and to use different passwords for different retailers.
A Tesco spokesperson said: "We continue to advise customers to use different passwords across their accounts to be as secure as possible online."