March saw a huge increase in the amount of spam offering financial deals, according to a survey by Email Systems.

The email management company said that financial spam accounted for over 40 per cent of all spam, predominantly offering share tips on stock supposed to increase in value. Email Systems attributes this behaviour to it being the end of the tax year.

"Obviously the share emails are a twist on the classic financial scams which we see so often," said Neil Hammerton, chief executive at Email Systems.

"But what is interesting is that this activity coincides with March, when many financial organisations are aggressively marketing their products to consumers before the end of the financial year.

"This is another indicator that spammers and scammers are becoming increasingly adept at identifying key interest factors likely to encourage consumers to part with their cash and are targeting their mails accordingly.

"Spamming is no longer just a numbers game. The output has become so sophisticated that consumers need to be extremely vigilant to ensure that they do not mistakenly believe a spam mail to be from a legitimate source."

There has also been a corresponding drop in the number of medical emails purporting to sell anti-impotence and anti-cancer drugs. Medical spam had been running at rates of 45 per cent but in March dropped to barely 20 per cent of the total.

Overall spam rates remain high, at over 90 per cent of all emails. The worst day was 27 March, when legitimate emails accounted for under 2.5 per cent of the total sent.