is that 'Westminster Council's 100 parking enforcement cameras have been in use since 2006 and can clearly read vehicles' registration plates.' Can clearly read reg plates. Why fix something that isn't broken?! Surely the act should be changed to accommodate systems that have been working well, or it would be pointless.
I've never seen the Department of Transport guidelines, but the Information Commissioners guidelines, which are far more extensive, do not state a minimum image resolution, rather a % of the screen that the target fills.
This is a lot more realistic goal, as you could have a 720 x 576 image with a number plate only filling 10% of the image, whereas a better targeted, but lower resolution image would give a clearer result.
By the way, 720 x 576 is DVD resolution, whereas analogue CCTV uses 704 x 576, normally called D1 or 4CIF. So whoever wrote the rule is a first class idiot.
Digital CCTV cameras often use VGA resolution, 640 x 480, but many manufacturers are switching to 1.3mp, 1280 x 960, which is 4 x VGA, or even higher. These resolutions seem low by digital camera standards, but the sensors are better and have to stream 25fps without fail, not something that your average digi cam can manage.
I saw a demonstration of a camera last week that gave a 37 megapixel 360° image, very nice, but hugely expensive...