Operation Sprogwatch: Keeping tabs on the kids

The reason this isn't snooping is simple - when you poll it, the unit vibrates, telling the carrier that someone is concerned.

The difference is pretty clear, if you read the Spyphone blurb:

Simply enter the secret access menu and program any mobile/landline number. Now dial the phone from that stored secret number and you can listen into the immediate surrounding sounds and conversations. The phone shows NO indication you are listening in thus can be given to your children for example and used as an everyday mobile phone without arousing suspicion.

Also, it emphasises that there are "other inferior copies" of this which blank the screen when you dial in, warning the phone user that it is being monitored - Spyphone doesn't. Your only problem is getting the child to carry it, and it looks exactly like a normal Nokia.

The idea of using a normal phone to provide an equivalent service, says Murray, is impossible. "I'm no electronics expert, but after working on this project for five years, I know what we're doing, and I have a team of experts with me.

"So, for example, when we recently had a presentation from a group which was claiming to do something similar with a BlackBerry, and they told us 'We monitor the GPS unit every three seconds', we knew it was nonsense. The BlackBerry battery can't stand that sort of load."

The main technical innovations in the buddi unit are the antenna and the battery. The battery is substantially higher capacity than most phones – a 3.8V Lithium Ion battery with 600mAh capacity and power consumption of 15mA, giving a battery life of typically 40 hours, or 60 hours standby. "The main saving on power is the fact that there's no talk time," says Murray. This isn't a phone, and you can't flatten the battery chatting or texting or browsing.

'Signal almost everywhere'

What they found when they started the project was that the primary problem with mass market GPS devices was that the antenna simply wasn't sensitive enough. "We went to Fractus in Spain, and they designed our GSM antenna from the ground up, which is why we can be smaller. And they tuned the GPS antenna, making it sensitive enough to get a signal almost everywhere. But there was nothing equivalent on the market, as we quickly found... and you can see why – nobody in their right mind would have done it. Or maybe, anyone in their right mind would have given up."

Sara Murray didn't give up, because she sent her daughter on a skiing holiday. Sara herself is an outdoors person, participating in sailing, skiing and running at a high level. "I sent her off with nothing more than a piece of paper with my mobile number on it, tucked into her pocket somewhere, and I thought: 'There has to be something more useful I can do…' and it became a mission."

Apart from the maternal motivation, Murray is a remarkable innovator in any direction. She founded an online insurance website called inspop.com - it was bought by Admiral group when it got to a quarter of a million users, and rechristened www.Confused.com – and she has other notches on the stick for achievements such as Ninah Consulting.

She was a finalist in this year's BlackBerry Awards for Women in Technology. Whether this makes her a Modern Muse is yet to be decided, but the company is on track to sell 10,000 units in the UK this year, and is eyeing distribution in the US, Australia and South Africa for next year.

And unlike Kevin Warwick's subcutaneous NFC chip, this device actually works. ®