If you read nothing else in this article, hear this: do not try to post something after security. Most of these counters are in the arrivals or check-in areas, not airside. The small postal point in the departure lounge of Terminal 2 is the only exception, and it only sells stamps for letters under 100 grams. So if you’re holding a giant teddy, post it before you fly.
I once saw a businessman furiously trying to mail a contract from the business lounge. He had to leave security, find the post desk, pay a re-entry fee, and miss his flight. The moral of the story? Heathrow is a sprawling beast—treat it like a wilderness expedition. You need a map and a plan.
