So the schemes will rely on entry point cameras like the London Congestion Charge, but with different zones depending on how close you get to the city centre?
Technologically, it might stand a cat in hell's chance of working if they keep it simple like the central London system: If you go in the zone, you pay a fixed daily rate. Though having multiple zones is going to confuse the crap out of people, with many opting to pay more than they need to for fear of being fined.
As for the idea of combining a box in the car to record mileages with external cameras to record zone entries and exits, it's utterly ludicrous. How on earth do they plan to correlate the two sets of data?
Besides, the London system only works because people are expected to report themselves if they enter the zone. In heavy traffic (which is the whole point, isn't it?) It's likely rather than just possible that the entry and exit cameras won't get an unobscured view of your number plate. It wouldn't be so bad if a camera missed you on the way into the zone and you continued to be billed at the lower rate, but what if you're missed coming out of it and end up continuing to be billed at the higher one?
These ministers need to go on a course to explain to them exactly what the technology is capable of before they start spouting hair-brained claptrap like this.
On the subject of the London system, I'm amazed they haven't come up with a similar arrangement for speed cameras. If you think you've been caught, you phone a number and pay a reduced fine. If you take your chances and you're actually collared, you get the full fine and points as usual. Forget replacing the film reels, they wouldn't even have to bother maintaining the cameras except to make sure that they still flashed. Seeing as it's all about money, surely that would optimise their revenue stream.
I really shouldn't come out with stuff like this. You never know who's reading. Some of these moronic government types might even think this is a good idea