Glen Goodman went aboard the WW2 cruiser on the Thames which reopened to the public today.
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The online guide offers easy, moderate or fast options. But some busy junctions are given the same risk rating as a quiet backstreet.
Misty and murky tonight. A band of rain pushing across London from the south west from 9pm onwards.
It could be the world's biggest open air trampoline. The bizarre project has the backing of London mayor Boris Johnson.