Directions to MIB from:

Heathrow Airport
Take either the Eastbound Piccadilly Line on the Underground to South Kensington and change to the Eastbound Circle Line to Aldgate.  Alternatively take the Heathrow Express to London Paddington, then change to the Eastbound Circle Line on the Underground to Aldgate.

Gatwick Airport
Take the Gatwick Express service to London Victoria. Take the Eastbound Circle Line on the Underground to Aldgate.

Stansted Airport
Take the Stansted Express to Liverpool Street Station and then take the clockwise direction Circle Line on the Underground to Aldgate.

City Airport
Take the Docklands Light Railway (DLR) to Bank.

‘Eurostar’ London King’s Cross Terminal
Take the Metropolitan Line on the Underground to Aldgate.