Hi,

What should the minimu transit time be in LHR if i had to go from terminal 1 to terminal 3?

thanks

goodo

Assuming your baggage is checked through, and you use the airside inter-terminal connection path, it would take you:

20 minutes to walk from your Term. 1 gate to the Connection Centre
15-20 mins., depending on queues, for security at the C.C. and check-in for your Term. 3 flight
15 mins. for Term. 3 connection bus latency and trip to T3.
5 minutes to navigate the T3 maze through to the departure lounge, or, as much as 15 minutes walk to your gate, if you're going directly there.

Total: from 55-70 minutes, depending. It can actually be faster to clear immigration, baggage, and customs, and push a trolley through the tunnel to Terminal 3, and check in again, but, depending on the airline, if you're in coach, the check-in queues as Terminal 3 can be very long.

In the other direction (Term. 3 to Term. 1), it's worth noting that the BA queue at the Connection Centre can be interminable, but there's no reason to wait there if connecting to a BA domestic flight since you can check-in at the BA domestic lounge in Terminal 1.

It varies greatly with the amount of people queued at security. I've done it in less than 30 minutes and I've had to suffer through 90 minute waits before. Don't go at the beginning or end of a U.K. holiday weekend.