The new anti-spam directive which came into force today will not stop unsolicited email, critics have warned.

Under the terms of the European Privacy and Communications Directive, businesses sending marketing emails to consumers will have to obtain express permission from the recipient.

And it will be illegal to send emails or text messages to mobile phones unless companies can prove an existing customer relationship for similar products and services.

Failure to comply could lead to a £5,000 fine for each offence.

But the directive will be crippled by the failure of nine EU states, including France and Germany, to comply, forcing the European Commission to begin infringement proceedings against them.

And the US 'Can Spam' proposal, expected to become law on 1 January 2004, works on the alternate opt-out principle, allowing businesses to send emails to people unless they ask not to receive them.

Graham Cluley, senior research analyst for antivirus and anti-spam firm Sophos, warned: "These laws won't make any difference at all.

"Since 95 per cent of spam comes from the US, if the US Can Spam becomes law on 1 January I think we will see a lot more spam, as this is a very weak law and pretty bad news."

And it is near-impossible to take legal action against spammers because of the difficulty in tracking them down.

"More than a third of spam now comes from hijacked PCs as the link between spammers and virus writers becomes more prevalent, and it is often sent through countries like Russia or China which have no laws against spam," he said.

But parliamentary anti-spam group the All Party Internet Group (Apig) sees the directive as a positive step.

"It is a small step forward, and as countries now see spam as a threat and not just an irritant they are taking it more seriously," said Brian White MP, the group's treasurer.

Organisations such as the National Hi-Tech Crime Unit, the FBI, the Office of Fair Trading and its US equivalent the Federal Trade Commission have built strong working relationships which will help stop spammers, said White.

Also under the directive, cookies may still be used as long as website visitors are made aware that they are are there. Users must also be given "clear and comprehensive" information regarding how their information will be collected and how it will be used, together with the right to object to that use.