Sussex Police have launched a review of their computer system after a virus brought virtually all of the force's 2,500 terminals to a halt.

Millions of pounds have been spent in the past decade on state-of-the-art technology, yet in seconds the Nachi worm threw the organisation back to the days of pen and paper.

Hundreds of officers and support staff were left staring at blank screens. People calling to report crimes had their details taken down on a notepad.

No members of staff were sent home but some left their offices and went on to the streets to help with crime-fighting initiatives.

One leading member of the Sussex Police Authority wants to know why and how the system failed.

Councillor Ken Bodfish said: "This has posed a very serious question as to whether the systems we have are adequate.

"We need to know whether we have proper protection. We cannot afford to have our systems shut down like this."

The worm affected Sussex Police from about noon on Tuesday. Almost all the force's computers had to be switched off.

Chief Superintendent Andy Bliss said: "The effect on the public was minimal. Officers were dispatched to incidents as usual and the emergency response was not hindered.

"There were some delays in phoning people back after they had reported crimes but the initial call and the police response to it was unaffected. We would like to apologise for any inconvenience this may have caused."

Mr Bliss said computers were slowly being switched back on.

The Nachi worm, which also affected some local authorities in Sussex, was created in a bid to destroy the MSBlast virus which has been infecting machines since July.

Despite its good intent the worm has caused problems of its own, forcing terminals to reboot every 60 seconds and slowing systems down.

It is thought to have infected Sussex Police via a laptop computer.