Identified Cameras

I have written previously about the strange cameras on gantries that are appearing on London's A roads. It would appear from the comments posted and some further research that these cameras are Automatic Number Plate Recognition cameras. What is not certain is for what purpose or purposes they are being erected, is it to enforce Ken Livingstone's Low Emission Zone which commences in February 2008, is it to enforce a road pricing scheme? I would just like to know.

UPDATE
The Institute of Advanced Motorists say they are to enforce the LEZ. I may be cynical but I think they could be used in the future for a Road Pricing scheme.