The personal details of more than a million people signed-up to customer loyalty schemes have been taken in a sophisticated cyber attack.
All of them have had their home and email adresses compromised, while half a million have had their credit card details stolen.
LoyaltyBuild, which operates getaway breaks for companies like Supervalu, AXA and Stena Line, says it identified the breach last month.
The Data Protection Commissioner, Billy Hawkes, says the company shouldn't have been holding on to details in the first place.
