May saw a resurgence in the amount of viruses in circulation and the number of phishing attacks.

The latest monthly report from managed security vendor MessageLabs noted that virus attacks, and particularly Trojan attacks, increased by a third month on month, in part due to the Bagel virus.

Meanwhile phishing reached its highest level of all time, after declining since January. MessageLabs logged over nine million phishing attacks in May, over three times the number in April.

"As the financial stakes increase, criminals have become much more familiar with the use of IT in the commission of these types of fraud and criminal activities," said Paul Wood, chief information security analyst at MessageLabs.

"Although any measure taken to update the law to address this trend is to be welcomed, the issue really needs to be tackled at source.

"Industry and government co-operation is essential to identify and shut down perpetrators, alongside a tighter legal framework and stronger enforcement powers.

"More specifically, ISPs should face up to their responsibility to protect their customers."