IT contractors and other information security professionals will never be able to completely protect corporate or customer data that is permanently stored, it is claimed.

Dutch researcher Dr Harold van Heerde claims that focusing on security alone is too narrow and attention should instead turn to making data disappear "like footprints in the sand".

Dr van Heerde, of the Centre for Telematics and Information Technology at the University of Twente, has looked at ways data can be made to "degrade" over time.

Stored information could be intermittently replaced with something more generic until it is largely irrelevant, he claims, which would also make firms think more carefully about what information they actually need to store.

"In most cases there's no good reason for them storing data for so long," he told the BBC.

The Information Commissioner's Office recently told firms they should make data security procedures "part of the company's DNA".