IT managers who orchestrate wireless marketing campaigns will increasingly have to take account of regulations in order to avoid legal pitfalls, and damage to the reputation of their firms.

Following a £50,000 penalty levied on Moby Monkey, a Leeds-based firm that was spamming users with SMS competition offers, experts say that a tightening of UK controls on mass messaging services is coming and that marketers will have to address issues of consent and privacy.

The Moby Monkey judgement - made at the end of August by premium-rate services regulator Icstis (the Independent Committee for the supervision of Standards of Telephone Information Services) - could deter aggressive wireless marketing projects. Many such projects are planned to take advantage of picture messaging, always-on connections, location-based services and other new features on phones and mobile communicators. Regulators say that without strict controls the new services could lead to users being charged for receiving unwanted emails, and could also cause annoyance and offence.

"With SMS text messaging there are a handful of companies that are abusing the system," said Steve Wunker, co-director of industry group the Mobile Marketing Association. "But wireless data devices may introduce new problems. There's an intense interest in picture messaging and Java."

By October 2003, the UK should have legislation based on an EU Directive on Electronic Communications that mandates explicit prior consent for promotional and advertising activities. But some experts believe that what marketers can get away with will remain unclear until at least that date. For example, it is unclear whether registering a number with the Telephone Preference Service - a tool that removes names from unsolicited voice call offers - protects consumers from text message promotions.

"Text (and email) messaging is a grey area of the law in terms of privacy and we have asked the Office of the Information Commissioner for guidance," said Icstis spokesman Rob Dwight. "Every time a new delivery platform has come on we see a handful of companies that try to exploit it for their own ends."

Legal experts said that wireless marketers need to act ethically to stay within the rules. "The general principle is you can't do this without permission and you must be clear in labelling messages, who you share data with, and how long you keep data for," said Joanne Brook, partner at technology law firm Sprecher Grier Halberstam.