Transmitter chips and GPS trackers are devices designed to help to trace a child's whereabouts. But do hi-tech solutions raise more problems than they solve?
By Megan Lane
BBC News Online Magazine
A month after the bodies of Holly Wells and Jessica Chapman were found in a remote ditch, a cybernetics professor known for his headline-grabbing stunts came up with a plan to microchip children to prevent them being abducted.
Professor Kevin Warwick, of Reading University, convinced the Duval family that a microchip implanted in their 11-year-old daughter Danielle's arm would ease their fears.
The youngster was nervous about going out alone, following media coverage of the Soham case.
If she went missing with a chip installed, it would send a signal via mobile phone networks to a computer, which would pinpoint her location on an electronic map.
But 15 months on, Danielle remains unchipped. "We never heard nothing more about it," Mrs Duval told BBC News Online. "Danielle is still nervous about going out alone. If she does go out, myself or my husband goes with her. She always carries her mobile around now."
Professor Warwick says the backlash against the scheme - numerous children's charities came out against the plan - forced him to reconsider. "I was perceived to be an ogre trying to do nasty things to children. The opposition to it made me think that ethically, this is something not deemed to be appropriate."
Someone to watch over me
The Duvals are not alone in their interest in child surveillance technologies. "Every week I get someone e-mailing me to ask if I can do something for their child," says Professor Warwick.
Research by nVision, the online database of the think tank Future Foundation, found that 75% of British parents would buy a device to trace their child's movements.
Just such a gadget is on sale in the United States - a GPS locator which can be locked onto a child's wrist - and the company, Wherify Wireless, is now eying up the UK market.
It picks up signals from global positioning satellites, and transmits the wearer's location to a central receiver. Concerned parents can log onto a website or use any phone to check their child's location to within several feet. Should danger be suspected, the child or parent can hit a panic button which alerts local police.
Others are developing wristbands which use radio frequency to set off an alarm if a child wanders outside the range of a receiver held by a parent, guardian or teacher.
There are RFID tags (radio frequency identification technology), which contain a silicon chip able to hold a large amount of data and an antenna able to transmit that information to a reading device. During the Iraq war, the US Navy used RFID wristbands to keep tabs on the wounded arriving at field hospitals. The US military is reportedly interested in developing RFID dog tags to track individual soldiers on the battlefield.
RFID chips are already used to tag pets and other livestock for identification rather than tracking purposes. The chips don't reveal the whereabouts of a missing puppy, but if the dog is found, a vet can use a reader to find the pet's unique ID code and from that get the owner's details.
False sense of security
Chris McDermott, of the anti-RFID group No Tags, says chip implants would be of little use in tracking a missing child as readers only have a limited range.
"What parents like the Duvals want is an implant which can be traced by satellite - but that's a long way off. Let's face it, all such a chip would do in cases like Soham is allow the police to trace the bodies more quickly. No technology would have saved those girls."
Michele Elliott, the director of Kidscape, dismisses hi-tech tracking gadgets as "ridiculous gimmicks". Not only would such devices make children fear they are at a greater risk of abduction than they really are, says Ms Elliott, the children wearing them may become complacent if they think technology - which can fail - will take care of their personal safety.
Witnesses may not realise that anything is amiss
"Teenagers who don't want to be tracked are not going to wear them. What are you going to do - sit on the computer all day, every day, tracking your child's movements?"
Then there are concerns about the long-term health effects of such devices, especially microchips transmitting signals from inside young bodies.
Instead, parents should teach practical strategies that will keep their children safe for life. The charity provides downloadable leaflets [see internet links on right] with advice such as arranging meeting places in case you get separated, and having a codeword so that if someone else has to collect your child, they can signal it is safe to go with them.
Existing technology also has its uses.
Many children now carry a mobile phone as a matter of course. Their location can be traced by triangulating the signal - if the phone has not been switched off.
Mobile phone technology was a key part of the police investigation into the murder of Holly and Jessica.
By working out which ground station Jessica's phone was using, detectives were able to pinpoint its precise location when it was turned off.
The charity Milly's Fund - set up in memory of the murdered schoolgirl Milly Dowler - encourages teens to teach their parents to use text messages to stay in touch.
Last week, the Dowlers helped Surrey Police launch the Child Rescue Alert system. The force is the second in the UK to set up the system which sends out alerts on local media and mobile phones when a child is abducted. It is based on a US scheme, Amber Alerts, which is in use in 15 American states and has helped more than 100 children return to their families.
WHEN IS AN ALERT TRIGGERED?
The missing person is under 16
The child is believed kidnapped
Senior officer fears death or serious harm
Description available, eg photos of victim or suspect, number plate of snatch vehicle
So far, UK police have issued just one alert, when six-year-old Summer Haipule was feared abducted in Brighton (she was later found asleep under a cot in a neighbour's house).
Because for all the fear about strangers who may pose a danger, just a fraction of the children murdered each year die at the hands of an unknown assailant.
Kidnaps and murders by strangers are no more common than 20 years ago, according to Home Office figures which show there are, on average, six such deaths a year.