Heathrow Terminal 5 handles more passengers than any other terminal in the UK – even when busy single-terminal airports are included. In September an average of 100,000 passengers arrived or departed each day from T5, which is the main hub for British Airways.

As of 2026, Terminal 5 is consistently the most crowded terminal at London Heathrow (LHR), primarily because it serves as the global hub for British Airways. While it is the newest and most modern terminal, it handles nearly half of the airport's total annual passenger traffic—roughly 35 to 40 million people per year. During peak morning and evening "banks" when long-haul flights arrive and depart simultaneously, the security lines and the internal transit train (connecting the A, B, and C gates) can become extremely congested. Terminal 2 (The Queen’s Terminal) is the second busiest, serving the Star Alliance carriers. While Terminal 3 and Terminal 4 handle significant volume, they often feel less "overwhelming" because they host a larger variety of smaller airlines with staggered schedules. Heathrow's record-breaking traffic in 2025, reaching over 84 million passengers, has put immense pressure on Terminal 5, leading to ongoing investments in automated security scanners and biometric boarding gates to help manage the dense crowds and maintain the flow of travelers.