On 20/01/2012 21:29, Roland Perry wrote:
[London Congestion Charge)
There's also some enforcement by foot patrols, although I've never been
sure how widespread they are. That's because you have to pay by the day
once inside, which can't be enforced solely by entry cameras on the
periphery.

There aren't any foot patrols - rather, there are mobile camera vans
(dunno how many there are - maybe even just be the one?) that position
themselves on roads inside the zone:

http://www.flickr.com/photos/aderowbotham/56561330/
http://www.flickr.com/photos/adinazed/6191499533/
http://www.flickr.com/photos/photo/205582779/

There are also fixed cameras on some key routes inside the zone, in
addition to the fixed cameras at every entry/exit point around the
periphery of the zone.