New European laws come into force today aimed at curbing the stream of unsolicited emails that chokes the inboxes of most internet users, but spam experts have condemned the measures as toothless and loophole-ridden.

The EU regulations make it a criminal offence to send unsolicited commercial emails or text messages unless the receiver has agreed in advance to receive them.

The government described the law as a "step in the right direction" in the fight against unsolicited emails. Net users may not notice a reduction in the number of junk mail messages they receive, however, as most spammers are located outside EU jurisdiction.

The Spamhaus Project, a global spam-fighting organisation, estimates that spam make up 60% of all email traffic on the western internet, with 90% of the junk emails received in the UK originate in the US.

"Britain's much anticipated anti-spam law has been rendered toothless and will now do very little if anything to stop spam in the UK," Spamhaus said in a press statement.

Spam expert Lindsay Marshall, a computing science lecturer at Newcastle University, also criticised the legislation.

"The problem is that almost all spam originates from outside Europe, particularly the USA, but this law applies only to the European Union. This law is the right idea in principle but to be honest, it will have no noticeable effect," he said.

Firms using tracking devices such as cookies on their websites will also have to tell users and provide an opportunity to reject them.

Businesses which have established relationships with their customers are exempt from the new laws, in an attempt to ensure that business-to-business e-marketing is not affected.

Spamhaus is also concerned about this exemption.

"Britain's firms will continue to suffer the onslaught of ever more spam, now from spammers claiming legality. The likely outcome of this is that addresses deemed to be "business" such as "sales@company.co.uk" will be rendered useless for anything but receiving adverts."

Companies or individuals that break the laws can be reported to the office of the information commissioner, which has powers to take them to court.

The penalties imposed by the EU Directive on Privacy and Electronic Communication have also been criticised by Spamhaus.

The law states that companies in the EU that continue to send spam will face fines and, in certain circumstances, can be sued by the recipients.

In the first instance, magistrates can levy fines of up to £5,000 - a sum Spamhaus described as a "mere slap on the wrist" for spammers who can net thousands of pounds a week from their activities. However the organisation can also be referred up to trial by jury, where there is no limit to fines.