Peter Hendy, the Transport for London Commissioner, has said Crossrail 2 is needed because London's population is growing by "a tube train a week".
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Police said they are "extremely concerned" for the welfare of a "vulnerable" mother and her two children who have gone missing in Bexley.
It is hoped the 7,400-mile journey will become a cost-efficient and time-saving way of transporting trade between China and the UK.
The Supreme Court is set to decide on whether disabled travellers are legally entitled to have priority use of wheelchair spaces on buses.