Sending unsolicited spam mail is now a criminal offence in the UK under new laws which came into force today.

The rules — part of the EU's Privacy and Electronic Communications Directive — mean marketers must obtain permission from the recipient before sending junk emails or text messages.

But there are several exceptions to this rule. Those businesses already in a relationship with the recipient can email without permission. Corporate subscribers are also exempt, which means that much business-to-business marketing is not affected so your work inbox will probably see little change.

The rules also impose restrictions on websites that use tracking devices, such as cookies, demanding they tell uses why they are doing so and provide an opportunity to reject them.

"Breach of enforcement orders issued by the Information Commissioner is a criminal offence liable to a fine of up to £5,000 in a magistrates' court or an unlimited fine if the trial is before jury. Anyone who has suffered damages because the regulation has been breached has the right to sue the person responsible for compensation," said Communications Minister Stephen Timms.

However, as most spam originates from outside the EU its unlikely the rules will present much relief to UK internet users.

Over the pond, US Congress approved so-called opt-out rules on Monday, which demand unsolicited emails include a mechanism for recipients to indicate they do not wish to receive further mail. The rules, which are due to be enforced into national law early next year, also prevent senders from disguising their identity by using false return addresses or misleading subject lines. A breach of these rule could, in exceptional circumstances, result in a prison sentence of up to five years.

The opt-out rules have been slated by anti-spam group Spamhaus and The Coalition Against Unsolicited Commercial Emails, which called the proposals "really disappointing". Both organisations are in favour of adopting the European approach where email users opt in rather than out of receiving email.

For more information go to the DTI's site.