Study shows sharp rise in computer crime losses at US businesses in 2007.

First details from an annual survey by the Computer Security Institute reveal the average annual loss for a US business has risen to $350,424 (£172,743) – double the $168,000 (£82,800) reported in 2006.

The study also reveals that almost a fifth (18 per cent) of those that had suffered a security breach had experienced a targeted attack.

For the first time financial fraud has overtaken viruses as the biggest cause of monetary loss.

The full findings of the study are released tomorrow.