Transport for London's latest figures state that for the first quarter of 2011/2012 the average traffic speed on major London roads for the 12 hours between 7am to 7pm was 19.33 mph and over the same period was 8.98 mph across Central London.
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Londoners are being warned to expect transport delays over the Easter break, with roads jammed and some rail services shut down.
The lukewarm reaction comes a week after the prime minister name-checked the mayor as a possible successor.
At 15 metres high, make a dramatic entrance at London's Hayward Gallery.