White Horse, Longford, UB7
One of the oldest pubs in this part of London and very pleasant it is too, right near the end of Heathrow's runways. A sign on the pub suggests the building was put up in the mid-16th century, and it's definitely been a pub since 1601. There's a bar in the former barn to the rear (on the right side).
Address: The Square, 530 Bath Road.
Owner: Enterprise Inns (website).