Long Layover at Heathrow

Depends on what terminal. There is Costa coffee (like a Euro version of Starbucks - try the Linzer tarts!)

You can also go on the Heathrow website and see what shops and restaurants are in which terminals. There are alot of restaurants, and lots of duty free shopping (even Harrods!) and Boots to get toiletries, etc at for cheap prices.

It is one of my favorite airports because it is more like hanging out in a mall!

If your layover is something like 10-12 hours, then you can, in theory, take the Tube into London for a few hours sightseeing. Since I am confident that things will go wrong whenever they have the smallest opportunity to do so, for a shorter layover I would stay put.

We will be on BA so terminal 3 or 5 ~layover is 3 hours

By the time you disembark, go through passport control and find out from which gate your next flight is leaving, you will have a good deal less than three hours. Oh, and do you have to change terminals?

If your final destination is outside the UK, then you will stay "airside" and not go through passport control or customs. (You will have to go through security again.)

First, find out if your departing flight is from the same terminal in which you arrive. If it isn't, you'll have to change terminals. You can also do this airside.

If your final destination is in the UK, you will go through passport control and customs. From there you'll check in for your next BA flight either at your arriving terminal or another one.

For information on shops, restaurants, transfers, etc, go to: Heathrow Airport

Ck into Windsor castle and walk to Eton college from there lots of good restaurants on main st.. 20 min from Heaththrow.

Three hours is not enough time to leave the airport.