@ Hidden Costs
"It all sounded so great when the idea was scribbled on the back of a fag packet."
Not a chance. Fag packets are known for producing good designs that work. I bet you a GSM jammer to a doughnut this was Powerpoint..
It's a fantastic idea. I can see this work in London where GSM capacity is already so maxed out it breaks Critical National Infrastructure conditions - it'll make the effect of a successful bomb even more interesting by fully automatically jamming the emergency services.
Oh, and as for monitoring, I'm sure than any MP supporting this system will, of course, have this system installed first and make the data available where his/her tax payer sponsored limousine has been - after all, they're paying for it. AFAIK they have nothing to hide, no?
Even if it would be a plausible idea and it would dial a special number to avoid emergency service DDOS, I would probably only trust the Swiss to design it so it actually does as it says on the tin/specs. Every other so-called democratic government has shown themselves at their Stalinistic best over the last decade or so and have lost the trust of their citizens to act in their interest.
Anyway, I have to go, someone's buzzing my house with a helicopter. No, it's not a black one :-)