The has drawn up the guidelines, which require marketers to clearly identify themselves when sending messages.
Other significant requirements include obtaining explicit consent from consumers before sending a text message, unless they are offering similar products to existing consumers, and ensuring that all significant conditions for a marketing campaign are stated in the initial text message.
Marketers must also tell consumers how they can access details of promotional terms and conditions. Regarding premium rate phone lines, marketers must make charges clear from the outset and customers must not be charged at premium rates for opting out of receiving further communications.
In 2002, only 65 complaints were received by the Advertising Standards Authority about SMS campaigns, but in 2003 this rose to 393.
Andrew Brown, chairman of CAP, said: "It is important that marketers targeting consumers via their mobile phones conduct their business responsibly in this very personal marketing medium.
"This help note will help to ensure that anyone planning to send mobile marketing understands fully what is expected of them and that consumers receive fewer unwanted messages -- helping to safeguard the effectiveness of those messages they have opted in to receive."
At the same time, there were reports yesterday that Orange and O2 are to switch from an opt-in policy for adult content to an opt-out one. This would mean that all of the companies' contract subscribers could receive over-18 content, such as pornography, gambling and games.
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