Big Brother or friendly helper?

By BBC News Online's Orla Ryan

Fallen off a cliff?

As you lie on that precipice, you will probably feel quite glad that thanks to the latest mobile phone technology, the emergency services can tell where you are to within about 15 metres.

Or maybe you haven't been entirely honest with the Inland Revenue? Tax inspectors may deduce that your paltry salary doesn't quite match the champagne and caviare lifestyle implied by the data processed through your third-generation mobile phone.

It is essential this isn't marketed as Big Brother ... the key is that you have a greater ability to get what you want

BT Cellnet

As mobile phone operators prepare to launch third generation mobile phones - offering services most users will find helpful - some civil liberty groups are raising questions about the potential cost to privacy.

Keep it private

Few people want their exact moves to be public knowledge, for personal or professional reasons. Exactly how compelling it is to watch other people's every move was illustrated by the popularity of the Big Brother television programme on Channel 4.

But without the draw of either celebrity and cash, there are few who would sacrifice the right to privacy.

It is like putting an electronic tag on half the population

Caspar Bowden, Foundation for Information Policy Research

At present, it is possible for mobile phone operators to track your movements.

Most users are more than happy for people to know where they are, as they can get help finding a cash point or a good restaurant.

With third generation mobile technology, more powerful software will be deployed, allowing for automatic location tracking, Caspar Bowden, director of the Foundation for Information Policy Research, said.

These new technologies allow for a handset to be located within 15 metres, so it should be even easier to get help in finding what you want.

Follow the money

If and when these phones become a kind of "digital wallet", then mobile phone operators will know what you are spending your money on, Ian Brown, a researcher at the University College of London said.

What this could mean for individuals is that they will receive targeted advertisements.

For the mobile companies, it could mean a chance to recoup the hefty sums paid out earlier this year for third generation licences.

Mobile phone users signing up to special discount offers may find that the hidden cost is allowing the mobile company to send you special offers to buy a meal in a restaurant you happen to be walking past.

"What will happen with location-based services, it will be an opt-in service, if you want to be contacted [ you can be]," a spokeswoman for Vodafone AirTouch said.

Mobile phone companies have to walk a marketing tightrope, BT Cellnet says.

"It is essential that it is not marketed as a Big Brother," James Tipple, head of location-based services at BT Cellnet. "The key is that you have a greater ability to get what you want."

Consumers should have the option to decide what advertisements they want or how often they receive them, as well as the chance to turn off the facility, he says.

No such thing as a free lunch

Even if this information isn't used to market unwelcome promotions to you, somewhere there sits a mass of data that paints a picture of your life, argue campaigners.

With the new powers received under the Regulation of Investigatory Powers Act, many government organisations can get their hands on this data without any judicial or Home Secretary authorisation.

"The privacy risk is that once the information is available on a non-warranted basis, anyone who really wants to find exactly where you went [can], it is just going to be a question of paying money to private investigators," the Foundation for Information Policy Research's Caspar Bowden said.

"What we are talking about is the invasion of privacy and restriction on civil liberties by this information being available as a tool of surveillance."

This "enables this tool to be put on half the population. It is like putting an electronic tag on half the population," he added.

How true is true?

Also, a question can be raised about the accuracy of deductions made from this information.

It may help the police authenticate suspects' alibis, by tracking the whereabouts of their mobile phones.

But then again, it may also help criminals to create alibis by simply loaning their mobile phone to an innocent party.

Confused? Maybe you shouldn't have read this far.

But hey, that's a secret between you, us and whoever is monitoring your internet usage at work.