12 hour Heathrow layover

with difficulty, I fear - by the time you are off the plane and through security, it may be too late to get the tube into London. Unless you like drinking and clubbing all night, I struggle to know what you could do there.

I can only recommend the airport hotel. :-(

Is your luggage checked through?

As has be mentioned your only option is as mentioned to head in to London for a night out. Research which venues will be open latest and head out, then head back to Heathrow on the tube for your flight. I wouldn't drink too much in case you miss your flight.

It kind of depends on your interests really and which day you are there on.

If you have a good camera and tripod and are willing to put some shoe leather on the pavement there are great opportunities for night photography - Westminster area, south bank, St Pauls.

If it is a Friday/Sat or Sat/Sun then there will be ample places to get lit and tie one on before rolling back to the airport half cut from the West End (but not missing your flight of course). That's not for everyone of course but it would be my personal preference in your circumstances.

Otherwise, yeah, options are limited although you could always book a hotel in centrallish London, get a late dinner if you're hungry and then get up early-ish for an early morning wander before heading back to LHR.

Of course if you do try to check in obviously not in a fit state then the airline can refuse to let you board.

The real answer is that you cant, certainly not for a reasonable price, unless you have friends who can look out for you.

There are too mnay ifs - punctuality of flight - allow a couplahours in the mad rush at a morning check-in and securiy - no certainty of transport links to/fro London.

I'm just gonna start walking...

There are tube links (highly likely) within your arrival and departure time and there are 24h transport from-to LHR.

A bit of research, and depending on how tired you are, you could go in and wander around and then head back to the airport to sleep there for a bit.

tHE BUDGET AIRLINES DO BUSSES

at regular intervals that will take you to Victoria or Baker Street - some distance from the centre [nightlife] if you're looking for night life. And mybe a bit of a hassle if you have luggage.

Try here and see if anyone has any suggestions or will be in a similar predicament:

couchsufing.com

Okay, I'll be on the lookout for this because I'll only have my backpacking pack. Not checking any bags.