An additional 1,200 troops that were put on standby for the Olympics last week will be deployed, Culture Secretary Jeremy Hunt said today.
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The problems appear to have been caused by a power supply problem in Queen's Park in north west London, which has affected signalling.
Cloudy conditions continuing overnight, with some patchy outbreaks of rain.
The mayor has revised his proposals for a six-mile East-West cycling superhighway in a bid to cut traffic delays.