One day in London
 

I will be in London for one full day in May. This is an overnight layover, so i will need to get to the airport by early evening.

Should I stay at the airport and take the train into London? Visit the BM and eat at a pub?Any suggestions for sightseeing and a hotel will be appreciated.

What time are you arriving?

The previous evening.

If you get in fairly early that evening, I'd stay in central London. Are you arriving at and leaving from Heathrow? If so, I'd pick a hotel near a stop on the Piccadilly line (dark blue) - this is the line that goes directly to Heathrow. Bloomsbury would be a convenient area for that and the British Museum (Holborn or Russell Square stops). Plan on at least an hour to get back to the airport, plus time to get your luggage from your hotel.

As for what to do with your day, just pick the one, maybe two things that interest you most. What I'd do may not be what you'd do. If you're up to it the evening before, you could go to the Westminster area and see Big Ben/Parliament, Westminster Abbey, the Eye and the Thames, all lovely at night.

Unless you arrive late at night - after 10 pm - I would head into London and be able to spend most of the day there before heading to the airport.

If you can get an early start you can see the outside of some major sights and then visit just one or two major sights (depedning on which - some will take at least 4 hours to see much).

Arriving in Heathrow about 10 PM. Would like to have someone recommend a hotel at the airport that is inexpensive. Think this would be a better plan than staying in London with the luggage.

"<i>Would like to have someone recommend a hotel at the airport that is inexpensive. Think this would be a better plan than staying in London with the luggage.</i>"

Since your flight out isn't until the next evening I would not stay near the airport. You can leave your bags at Left Luggage at LHR. I'd stay stay at a hotel anywhere along the Piccadilly tube line and just take my carry on. What is your budget?

I did not realize I could leave my luggage at the airport overnight. For a hotel, up to USD200/night would be fine.
TIA

That is about £125 which is very doable for a single.

I don't know your exact date but here is one right next to the Gloucester Rd tube station which should be in your budget

http://www.millenniumhotels.co.uk/millenniumbaileys/

(there are other Millenium and Radisson hotels in the same neighborhood that would also work.