The average data breach can cost anywhere between £84,000 and £3.8m, depending on how quickly it is discovered and the type of information lost, says research.

The average cost is £47 per individual record compromised – except in financial services firms where costs rise 17 per cent to £55 per record, according to the study by the Ponemon Institute.

Data is mostly lost through third parties, said Joseph Ansanelli, vice president of data loss prevention solutions at Symantec, which sponsored the research.

"The fact that more than a third of breaches result from data being shared with third parties in the normal course of business is a clear signal that organisations should examine how they are sharing their customers' data with outsourcers, vendors, and partners," he said.

Companies suffering a breach see a 2.5 per cent higher than normal customer "churn" rate, which contributes up to a third of the costs incurred.

More than a third (36 per cent ) of data breaches are due to lost and stolen laptops or other mobile devices.