A survey of 201 companies by the National Hi-Tech Crime Unit (NHTCU) showed that cyber-crime cost this group of companies £195 million last year. Extrapolating the trend from this limited group to the wider UK business population, the cost would be much higher.

Detective chief superintendent Len Hynds, head of the NHTCU, said: "This research shows that some companies are suffering multi-million pound losses as a result of hi-tech crime. While it is too early to put an accurate figure on the total financial impact for UK business, all the indicators suggest we are talking about billions rather than millions."

Although only 24% of firms surveyed reported cyber-crime to the police - many fear adverse publicity - Dt Ch Supt Hynds claimed attitudes were changing but stressed sharing information was the only way to help internet detectives.