Over 900 million text messages were sent in January this year, according to research conducted by the Mobile Data Association.

The MDA attributes this growth to New Year greetings, but cannot confirm how many of these messages was actually just unwanted junk email - spam.

Sending spam text messages is a cheap advertising potion for marketing companies, which use it to target individuals directly. But receiving spam can be infuriating.

In the UK there are no specific laws to protect individuals from the constant stream of spam emails or text messages.

Last year, the European Commission proposed updating the Data Protection and Privacy Directive. It supported an 'opt-in' approach whereby people have to say yes to spam. But this doesn't apply to text spam.

Service provider Vodafone uses spam messages to notify customers of special offers - in the case of pay-as-you-go users it is the only point of contact - but the mobile telco insists it does not receive complaints from customers over spam mail.

"Customers can 'opt out'," said a Vodafone spokesperson. "Annoying them would be wrong as it takes a long time to win customers in the first place." Vodafone customers who do not opt out regularly receive spam messages.

BT Cellnet also operates under an opt-out arrangement.

"We do not pass on any numbers to other companies," said Vodafone spokesperson "The user will have to pass on their own number if they want to receive any other spam messages."

New legislation may place restrictions on unsolicited text-messaging. Until then, there's little users can do to stop the spam.