Mr Liu said the force had to consider easing administrative work for frontline officers if it wanted to address the problem of data leaks at its root.

Samson Tam Wai-ho, the legislator who represents the information technology sector, said the latest suspected leak showed the force might have failed to stop frontline officers using Foxy file-sharing software.

'There should be a thorough check of their computers to make sure Foxy software is deleted and a clear policy of penalising those still using the software,' he said.

But Mr Tam sympathised with officers who were not given sufficiently secure computers at work.

James To Kun-sun, a Democrat legislator, said the force could consider using Foxy to monitor leaks as a way to discover and stop them.

Computer security expert Michael Gazeley, managing director of Network Box, said that while leaks of police data received more publicity than most, they were just the tip of the iceberg. 'People just have no idea how serious the security issues related to peer-to-peer systems such as Foxy are,' he said.

'What we see every day is that there is a constant battle between security and convenience, and usually convenience wins.

'The problem is that if you have a secure computer and then you start using peer-to-peer systems, these sorts of things are going to occur. You are basically superimposing a completely different network over your corporate one.

'When you connect to the internet, it is very easy to forget that the internet is connected to you. People need to fundamentally rethink the way they are using computers.'