London Underground says that up to 5,000 people are at work under London's streets every night to work on maintaining the tube network. These essential works mean that the tube cannot run 24 hours a day.
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His top speed is believed to be the highest ever recorded in the UK by a rider carrying a pillion passenger.
The mayor took time out from City Hall to join Conservative party workers handing out leaflets in Uxbridge and South Ruislip.
No matter where you look, London's population is getting older - with the exception of one of the capital's boroughs.