The data base of UK company Watchfinder – one of the world’s biggest dealers in used luxury watches – has been “compromised”.

The security breach disclosed information about its well-heeled customers and their buying intentions.

A security expert said the company would be a “shiny target for hackers”.

Watchfinder CEO, Arjen van de Vall said in an email to clients:

“We recently discovered unauthorised access to a user account belonging to one of our employees which resulted in lists of our customers being compromised.

“We took immediate action, and the matter is being investigated.

“All our systems remain protected.

“The records in question may include your e-mail address, telephone number and/or any watches that you have purchased, or expressed an interest in.

“They do not include any postal addresses, passwords, credit card details or other banking information.”

Over the last ten years the used high-end watch market has boomed.

For example, some Rolex watches with a recommended retail price of £8,000 are being sold “unworn” for more than four times the value.

Other watches that have soared in price are Audemars Piguet and Patek Philippe.

Watchfinder warned customers to be wary of any “suspicious correspondence”.

The company said it has informed the relevant authorities and is conducting a further review of its security measures and policies.

Security specialist Ed Macnair, CEO and Chairman of CensorNet, said:

“Watchfinder’s cash rich client roster will have been a shiny target for hackers.

“Their email addresses and telephone numbers were the jewels in this heist.

“Stolen credentials are involved in almost half of all cyber-attacks.”