UK coppers were cut off from their main national criminal database for more than three days because of a computer virus.

Greater Manchester Police (GMP) was cut adrift from the Police National Computer (PNC) after finding the conficker virus on Friday. It meant police in Manchester had to ring up other coppers in different parts of the country to ask them to do national checks on names and vehicles.

Conficker was identified in the GMP system on Friday and quickly spread through the force. Assistant Chief Constable Dave Thompson said the virus was not destructive and no data had been lost.

It is not clear how such a basic worm could find its way into the secure police network. Conficker initially worked by exploiting a vulnerability in the Windows Server service, which Microsoft combated with a security update. The virus is now spread via memory sticks.