Travelling through London's Heathrow Airport has never been one of life's treats and a long-mooted expansion promises an ever more complex future. Argued over for many years, the plans include a third runway, more terminal space including satellite buildings, and an eventual capacity by mid-century of 142 million passengers a year from the current 80 million.
Simon Calder, resolute travel expert at the Independent newspaper, explains in apprehensive detail here: