Personal details of thousands of customers of Boots' dental plan have been stolen after a courier car was broken into in Bristol.
The information from Boots Dental Plan included customer bank account details, but officials claimed it was "highly unlikely" these could be accessed.
The details of 27,000 customers and 7,000 employees were stolen on 3 April.
Boots and Medisure, who administer the plan for the company, said all customers had been informed.
The Financial Services Authority said it had been given details of the theft and would be looking at the case.
'Complicated' format
The data tapes were stolen from the vehicle of a data security company while on a scheduled delivery to a Medisure office.
Avon and Somerset Police said they were investigating the theft from a car on St Thomas Street, but no-one had been arrested.
The data is described as "technically complicated" and only accessible with specialist IT equipment and software.
Medisure added the information was not stored on standard software or CDs and could not be used on any home-style PC or laptop.
A statement from Nottingham-based Boots said the firm informed the Dental Pan customers straight away.
Medisure said banks had been informed as a precaution so they could monitor affected accounts for any unusual activity.