The Heathrow Airport (County and London Borough Boundaries) Order 1993
This Order unites the whole of Heathrow Airport in Greater London, and in the London borough of Hillingdon by transferring areas—between Buckinghamshire (district of South Bucks) and Hillingdon (article 3);from Surrey (borough of Spelthorne) to Hillingdon (article 4);from the London borough of Hounslow to Hillingdon (article 5).