The admission means that many of the community groups campaigning against the building of these masts will now be able to seek judicial review of other planning applications that have been dealt with through the accelerated "Prior Approval" procedure.
The decision has pleased residents in Ballymacashen, Northern Ireland, who sought the review after the mobile phone company Orange erected a mast near a residential area last September after using the fast-track approach.
Their campaign was supported by the Northern Ireland Families Against Telecommunications Transmitters (Nifatt) who want to ensure that, in the future, phone masts are not erected within 300 to 500 metres of residential properties.
Margaret Dean, founder of Nifatt, said the decision was wonderful news for the residents. "It's a huge boost for our campaign and it gives us hope for the future. If the Government and industry won't listen to us, at least the courts have now recognised that if procedures aren't followed then they will decide it's illegal.
"We're not opposed to masts or mobile phones but we are opposed to putting them so close to people's homes and schools."
Most of the groups cam-paigning against such masts object to them on the grounds of possible health risks.
The priority approval procedure, which allows masts to be erected 28 days after planning application is sought, means that many communities find mobile phone masts erected close to housing and often with little consultation between residents and the companies installing the masts.