Six in 10 marketing professionals admit to having lost customer data after a security breach and nearly 90% of these cases are not revealed to customers, according to research by internet security company StrongMail.

The survey also revealed that a minority of businesses would give out customer information to third parties if it resulted in a sale, with 20% prepared to give out credit card details and 7% to reveal someone's sexual orientation.

"Businesses have a moral, ethical obligation to keep private, personal customer data safe and secure," said Paul Bates, managing director of StrongMail UK.

"They should not be handing it out to third parties in the hope of making a fast buck. If they choose to do this and then lose customer data, then they should at least be obliged to admit it."