The British National Party data leak that exposed thousands of members' details illustrates the insider threat to data security, says an IT log management firm.
Indications are that the list was released by an internal member of staff and not stolen by an external hacker, said Ross Brewer, managing director at LogRhythm.
"A similar incident could happen within any company or government body in the country," he said.
The majority of IT professionals believe insiders pose a more serious threat to data security than outsiders, according to a study commissioned by network firm Cisco.
Some 20% of more than 2,000 IT professionals surveyed across the globe identified disgruntled workers as data security risks.
The study found 11% admitted stealing data or corporate devices, selling them for a profit, or knowing of colleagues who did.
Some employees admitted keeping corporate information after leaving their jobs for various reasons, including malicious intent, the study found.
According to Brewer, all access and transportation of sensitive data should be strictly controlled.
"All user interaction should be monitored and supported with automated detection systems," he said.
BNP members have expressed concerns about potential backlashes and job losses after being exposed as members of the far-right party.
It is illegal for armed forces personnel and police officers to be members of a political party and other are in roles where membership of the BNP may be frowned upon.