what to do if in London for just one night?

At Heathrow you probably won't get through immigration and on the tube/train until about 9:00-9:30. That really doesn't give you time to do anything. I'd stay at a hotel near the airport or take a cab to Windsor. At best take the tube to Earl's Court and get a hotel there. Eat a good dinner and rest. Sleep in and eat a good breakfast then head to the airport. You will need to be at the airport no later than 9:30.

The only thing I would try and do is find an interesting hotel or restaurant near Heathrow. Arriving that late you really cant get to London in time to do much other than sleep-; and then you have to leave London too early the next morning to see or do anything. Not a creative answer.

So on a Saturday night in London the best thing to do is sleep in a hotel? =/

It's too late for a show, you're going to be tired from the flight... you could go out to dinner, or to a pub... maybe take a night bus tour. You're looking at 9:30 or later before you'd even actually be in London.

Sounds like your only option is a night bus tour. You can really see alot of this fantastic city under lights. Worth cking with the visitors bureau in advance so you have a schedule you may not get to London proper til after 10pm. They may also offer a public bus that would give you major tourist routes/sights. Unfortunately Underground shuts down about midnight so busses may also. it may be a short ride but better than none. In AM you could take Hop on and off double decker bus a real touist pleasure in case you miss the night tour.

Due to the time scales, Windsor would be a good idea (unless you want to try not sleeping!). Try for a hotel there (or in next door Slough if Windsor is full). If you don't find anything to your taste in Windsor town centre, walk across the bridge into Eton - there are some nice pubs and restaurants there.

Don't forget that if you leave at noon you need to be at Heathrow by 9am. Trains on Sundays sleep in, too. So be careful if you decide to try to spend the night in London instead of, as suggested above, staying around the airport and getting some kip. Bet you'll have jetlag when you arrive at 1 am Florida time.

Oh, sorry, forgot to mention the weekend engineering works on the tube, and the rolling strikes just starting.

I would suggest taking taxi into Windsor which is a fifteen minute rides. The castle is beautiful at night with all the lights one. You could go to a pub. Then in the morning you could walk to Windsor Great Park and/or to Eton (both a 5 minute walk from the castle) then get a taxi at 9:30-10am back to the airport.

Find a bench and sit down and cry you dont have more time

I'd find a hotel near Heathrow, check in (so you can dump the luggage) and then get yourself into London and aim for either Covent Garden, Leicester Square or maybe down by the Thames and Houses of Parliament and just walk around and enjoy the sights of London at night. The fresh air will feel good after your flight and London looks pretty at night. Then return to your hotel and have a good start the next day. Of course if it's tipping down with rain, ignore this idea!

Maggie's idea is good. Just remember, the tube and most bus lines shut down around midnight. There is night bus service to Heathrow and you might want to investigate this so you don't have to take an expensive taxi ride back to your hotel....Most pubs will also close around that time......the other option would be to take the Heathrow Express into London. This costs more but is faster. Get a hotel in London and then explore. In the morning, take either the Heathrow Express or Connect back to Heathrow.

If you don't need much sleep, spending one night in London rather than a hotel near Heathrow is possible. You could stay at a hotel near Paddington Station where the Heathrow Express stops. Head to the places Maggie suggested. You won't have time for much except walking around, maybe stop at a pub or bar for a drink. Get up early the next morning to catch the Heathrow Express back to the airport!

Check for tube closures (planned engineering works) here: http://www.tfl.gov.uk/ . If the Piccadilly Line is unaffected, find a hotel near it, else take the Heathrow Express or a car service. Check in to your hotel, drop your bag, and head to a pub you have chosen at http://www.fancyapint.com/ and enjoy a pint of real ale. At closing and/or early the next morning take a self-guided walk. Rick's Westminster walk would be an excellent introduction to London. Enjoy London and don't even think of staying near the airport.

I think I should have been more specific. The stay in London will happen at the end of our trip, so jet lag will not be a problem. Also we will not have bags (just a small backpack) because we will check it in Venice and won't get it back until it arrives in Tampa. No sleep or barely any sleep is no problem. I just want my fiance to get an idea of London so he would want to come back. Thanks for the suggestions!

I just posted a note on which hotel at Heathrow for you. If your are flying in at 8pm and leaving the next morningat noon, then, if it were me, I would for sure stay at the Sofitel Hotel that is at Terminal 5. Your are probably going to be to be exhausted but still awake. Make your life easy and enjoy the evening at the hotel with a nice dinner then go to bed and get a good nights sleep. Since you are at Terminal 5, the next morning will be alot easier to catch your flight. You won't have to worry about catching an airport shuttle. You are there. Enjoy a breakfast and then go to check-in for your flight. Enjoy your trip.

BB police contacted me about my somewhat sarcastic sit down and cry answer not helpful as per police- my serious response is check in to the airport Hotel(it is pretty comfy but I forget how much) then go out get a cab for a three hour tour the city. not cheap but the answer.

I would go into London. As you only have a backpack, take the Heathrow Express and stay at a hotel near there. Check in, throw your packpack and then walk around, take in a pub, or get on a bus and take the night tour[INVALID]I found one that has late tours. Then, hop on the Express the next AM. I really like walking around the Wesminster area at night[INVALID]you can see Big Ben, Parliament, etc., and right on the bus line over at Victoria, there are tons of little pubs and cute restaurants.