Dixons Carphone says 5.9 million payment cards as well as 1.2 million personal data records have been hacked.
The breach comes as a result of a cyber attack dating back to to last July.
The company, which includes a number of tech giants including Dixon Travel, Currys PC World and Carphone Warehouse, say there is no evidence of fraud on any of the cards affected.
Dixons Carphone have released a statement reassuring customers that appropriate action is being taken.
Of the 5.9 million cards affected, Dixons insist that 5.8 million of these had chip and pin protection and that they had not been compromised.
However approximately 105,000 non-EU payment cards did not have such protection and had been compromised. They say they had contacted relevant card companies about this issue.
Consumer advisors Which? have advices people to be more wary of potential scammers in the wake of the data breach.
It’s a good idea to be extra wary about any emails or phone calls you may receive related to the Dixons Carphone data breach.
Unexpected events like this can be a magnet for scammers. #scamaware
— Which? (@WhichUK) June 13, 2018
Carphone Warehouse have started contacting those that they know have been affected by the cyber attack.
Hi Phil, only customers who have been affected by the breach will receive emails. These emails will outline any steps you need to take but please let us know if you have any further questions. – Chloé
— Carphone Warehouse (@CPWTweets) June 13, 2018