Reports on Northwestern TV news and the local press in Manchester say that the computer systems of Greater Manchester Police were effectively cut off from most of the police national computer for around three days. It's unclear whether the cut-off was caused by the Conficker worm or the PNC operators shutting off access to protect their own resources, but the police say the infection was caused a member of staff plugging an infected USB drive into an office computer system.
The problems started on Friday evening and spread over the weekend, downing internet connections and email access, and causing officers to switch to contingency plans which involved their phoning colleagues in other forces for urgent PNC information.
According to the Manchester Evening News, the police's IT staff worked through the weekend and managed to eradicate the Conficker worm by Monday afternoon.
This isn't the first time that Mancunian computer systems have been hit by Conficker as almost a year ago, Manchester council's computer systems were downed by the worm, costing the local government agency an estimated £1.5m to fix the problem.
In that incident the council was forced to write off a number of parking tickets. It is not known whether police in Manchester will also have to write off similar penalty notices due to the outage.
According to Jason Holloway, Northern European sales manager with SanDisk, the reports that the infection was caused by a USB stick underlines the fact that conventional USB flash drives are a key method for spreading these infections stealthily.
The infections can, he said, occur without the USB stick owner being aware of the infection, as was the case with the Ealing and Manchester council worm problems of last year.
"Virus scanning has to extend beyond the PC to all types of removable storage", he said.
"Better still, employees should only be able to use authorised flash drives that include on-board antivirus scanning. This ensures that users cant turn off, disable or work around the protection, and would stop these infections from spreading", he added.