David Blunkett and Tony Blair are supposed to be giving more details today about Labour's plans to
electronically tag even more offenders than at present.
Apart from unreliable "lie detector" tests (why are these not firstly applied to politicians ?), the latest soundbite policy seems to be promising to track not just prisoners on bail at home, as at present, but a wide variety of people who will somehow be magically tracked on the move, if they are near the scene of a crime or a designated "no go" area.
Will the mainstream media bother to ask a few technical questions about this soundbite policy ?
This hand waving concept is based on as yet unproven technology, and places an absurd reliance on Global Positioning Satellite and Mobile Phone location technology.
This may eventually work for tracking offenders in the wide open spaces of the USA (but only to the nearest 200 metres or so) where there is a Federally mandated E911 emergency services location infrastructure being built, but this does not exist in the UK.
GPS tracking needs a clear view of at least 4 satellites in the sky i.e. it does not work indoors, where the vast majority of sexual abuse happens., It does not even work in crowded urban streets, where the view of the equatorial geostationary satellite orbit low down in sky, because of our northern latitude, is blocked by trees or buildings. GPS units also do not work inside the favourite vehicle of kidnappers and abusers, a closed panel delivery van.
Since the GPS satellite signals were never designed to be a security mechanism, they are not two way, so the receivers can be easily spoofed to provide tagged criminals with alibis for their crimes.
Mobile Phone cell location can be several miles out in accuracy, due to the quirks of radio wave propogation and reflection, as demonstrated in the notorious Soham murders case, where, according to the Cell Location Data, one of the victim's mobile phones was apparently last used at least 5 miles from the relevant mobile phonne mast, and possibly somewhere in area up to 10 miles away, from the true location.
Fixed phone line electronic tagging of low risk prisoners on bail, who have little incentive to abuse the system, has its place in enforcing night time curfews etc.
The current and for the foreseeable future technology and national infrastructure, does not exist to locate tagged people on the move with sufficient accuracy to enforce "no go" areas around , for example, schools, or to prevent serious attempts by highly motivated sex offenders to spoof the system.
CORRECTION: thanks to those people who have reminded us that GPS satellites are mostly not geostationary about the equator.
"GPS has poorer coverage the further you go from the equator, but the GPS satellites are NOT geostationary, they are in a 55 degree inclined orbit, which gives poorer coverage away from the equator.
There are 4 augmentation satellites (WAAS and EGNOS systems) that ARE
geostationary that can also be used for navigation, but the 24 GPS
satellites are NOT geostationary."