A traveller who had just flown Delhi–London–Toronto posted a warning thread about the Heathrow connection; the replies filled in the practical details. Synthesized:
- Book at least a 2-hour layover at Heathrow. The core advice: the pain point is not changing gates at Terminal 5 — it's the security re-screening between connections, which the poster described as very slow and stressful on a short connection.
- Know the T5 layout. T5 has three gate areas: A is in one building, B and C in another. The gate change itself took the poster only 10–15 minutes (B to A); the queue at security before entering the gate area is what eats the time.
- Don't pack liquids in cabin luggage — even under 100 ml. The poster's follow-up after the trip: liquids in the cabin bag trigger extra checks at Heathrow screening; on a short layover, travel with none at all.
- Transit visa: not needed if you stay airside. To the question of whether a UK transit visa is needed on such connections, a member answered it isn't required when you're not changing terminal (i.e., remaining airside on a same-terminal connection). Transit rules vary by nationality and itinerary — verify UK transit requirements for your passport before booking a connection that changes terminals.
- Expect knock-on delays. The poster's onward flight boarded on time but still departed late — another argument for the longer layover.