Workers in UK businesses are not doing enough to keep their passwords secret and so are risking the security of their companies, a new study revealed.

According to Cyber-Ark Software, more than half of office workers keep their passwords and log in details on Post-It notes.

Worryingly, this figure also included company IT professionals - who admitted keeping administrative passwords written down in obvious places.

Similarly, the study revealed that one fifth of companies rarely change their administrative passwords and seven per cent said they never do this, meaning that ex-IT employees could potentially still gain access to sensitive systems and data.

Furthermore, it was found that eight per cent of manufacturer's default passwords were still being used. Hackers commonly gain access to computer systems by using these codes.

The vast majority (82 per cent) of IT professionals also said they keep important passwords in their head, which could hinder security efforts and business continuity.

"Companies need to wake up to the fact that if they don't introduce layers of security, tighten up who has access to vital information, and manage and control privileged passwords, then snooping, sabotage and hacking will continue to be rife," Calum Macleod, the European director for Cyber-Ark, explained.