More than a third of organisations who suffered a data breach in 2016 lost more than 20 per cent of their revenue as a result, new research claims.

A report from Cisco found that more than a fifth of breached organisations lost customers, with 40 per cent losing 20 per cent of their customer base.

It showed that 29 per cent lost revenue, with 38 per cent losing more than 20 per cent of revenue and 23 per cent losing business opportunities.

Dan Sloshberg, a cyber resiliency expert at Mimecast, said email is an organisation’s weakest link in terms of cyber security.

“It’s no surprise that spam, about a tenth of which is malicious, is at its highest level since 2010,” he said.

“Cyber criminals haven’t rediscovered this vulnerability; they’ve simply improved their tactics.

“Email accounts for 91 per cent of all cyber attacks, from botnet-sent spam through to carefully curated messages targeting and impersonating senior executives.”

The report found 90 per cent of these organisations are improving threat defences and processes after attacks.

More than a third are separating IT and security functions and 38 per cent are increasing security awareness training for employees.

Many UK organisations are still in the dark about how to approach spending on information security technologies.