When you do get to a London Airport, Mainline Train or Coach
Station
buy yourself, just like we Londoners do, an Oyster card -

it's the cheapest way to get around.
The Transport for London website is also a good overall guide.

London cabs are expensive but can be hailed on the street.
Mini-Cabs are cheaper.
Downtown Cars for mini-cabs from The Olde Salt Quay in Rotherhithe:
0207-231-0006
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