Sitefinder also shows which type of mobile phone signal is being used, the name of the operator, the frequency of the signal and the height of the mast.

Ofcom was ordered by the Information Commissioner to publish all of that information, including the grid reference of each mast in the country, in a single database file.

Radio network

It followed more than two years of requests from Ian Henton, of Health Protection Scotland, for the data under the Freedom of Information Act.

The request was made under the "general right of access to information held by public authorities" as enshrined by the act.

Ofcom had argued that supplying such specific information could leave the emergency services radio network open to abuse.

It also pointed out that the data was owned by the mobile firms and was supplied voluntarily.

Ofcom explained that if the raw data were available it would provide mobile phone competitors with a "springboard" from which to discover the design of each operator's 2G or 3G radio networks.

But the Information Commissioner disagreed and said the data had to be released.

As a result, mobile phone firms have stopped supplying all data to Ofcom.

A spokeswoman for the Mobile Operators Association said putting all the requested data into the public domain would "entail serious competitive and commercial issues for each of the operators".

She added: "The operators fully support Sitefinder continuing to be publicly searchable by postcode, streetname, or locality."

She said the operators were in discussion with Ofcom and the government on the future provision of data to Sitefinder.

'Remain optimistic'

In a statement the regulator said it was concerned that Sitefinder "would cease to be a valuable tool for the public" unless the mobile firms could be persuaded to continue handing over data.

Ofcom is now appealing the Information Commissioner's decision in the High Court.

It said it was optimistic of persuading the operators to resume supplying information.

"We remain committed to providing the Sitefinder service to citizens and consumers," said the regulator.

Mr Henton was not immediately available for comment.