The most recent annual report on congestion charging, a report the London authorities are required to produce, says that the practice has resulted in a 16% reduction in road traffic CO2 emissions in the (original) chargingarea compared to average 2002 levels.
Mr Hardcastle, of consultants Kellogg Brown and Root, said the main recommendation was for an "area-wide" charging scheme which would use satellite technology to monitor the journeys of all motorists and charge them per mile.