The proportion of unsolicited emails compared to all emails reached a record high of 97.02% during December 2007, according to figures released by UK email security provider SoftScan.

The figures indicate that less than 3% of all emails sent during that month were legitimate.

Despite several major arrests of spammers last year, including US "Spam King" Robert Alan Soloway, spammers still have the upper hand over law enforcement, demonstrating that there is not enough deterrent for spammers to give up their highly lucrative enterprise.

Usually, when you look through monthly statistics, you can quickly identify the weekends or major public holidays when there is less legitimate business emails sent as the spam levels jump-up. But in December, except for some slightly lower levels in the first week, spam has remained consistently high throughout the month.

During the same month in 2006, legitimate emails accounted for more than 10%, while spam accounted for less than 90%.

Until the authorities can get a grip on this phenomenon it will continue to undermine the effectiveness of legitimate email activity and depress the rates of response from campaigns.