So successful has the scheme been, that in February, London extended the charging zone westward.

FORBES: Magazine Article

Traffic delays are down by a third, while average speeds in the charging zone have increased by nearly 40%.

ECONOMIST: Traffic

Diplomats were settling congestion fee bills but now their offices are inside the charging zone, they have stopped paying.

BBC: NEWS | UK | England | London | Embassies suspend paying C-charge

Take the results TfL have published about the removal of the Western Extension of the Congestion Charging Zone (WECC).

BBC: London

The number of journeys spent crawling through the charging zone at under 7mph (10kph) is down by about a third since it began in February 2003.

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The combined effect of charging and improved vehicle technology, notably cleaner-burning diesel engines that are being used in more buses and taxis, has led to an overall reduction of 13% in nitrogen oxides and 12% in PM10 via vehicle tailpipe emissions in the charging zone.

FORBES: Paul Maidment

Mayor Ferguson said the issue was how to define the city centre in order to decide where to draw the charging boundary but he hinted it was unlikely to be the size of the residents' parking zone.

BBC: Road