Originally Posted by GUWonder

I do a lot of overnights at LHR hotels, often coming in on the last ARN/CPH/OSL flight of the evening and then flying out on the morning batch of flights to the US. As a US passport holder, with checked luggage at times, and sometimes using the Heathrow Hoppa or public free buses for hotels in/near the "free zone" in one or both directions, I end up having as little as 5 hours at my LHR hotels to as much as 10-13 hours even when my scheduled layover at LHR is 11-15 hours.

The only reason I would even consider going into Central London at night on such journeys would be to meet friends/family/go out; and all that only with the idea being that I would sleep well on my US-bound flight in the morning to get some sleep value out of my business class ticket. Generally, I would avoid going to Central London on such layovers, and would otherwise avoid it like the plague.