If you can get a direct flight it's about 12 hours. But usually most people have to change somewhere, which ups it to more like 15 hours (or more). I had an overnight stop in Moscow once and that was pretty diabolical -- fat snarling Russian ladies smacking us because we had fallen asleep with our feet on chairs, mineral water that tasted like licking granite, etc.
ANYWAY...
Oasis Hong Kong Airlines operates directly out of Hong Kong as their headquarters. Although they advertise themselves as a budget airline, they only fly between HK and London (Gatwick), or HK and Vancouver (Canada). Their website is pretty clear and easy to use. According to their own website info (follow the menu on the left here), they reckon the flight will be 11 hours 50 minutes getting out there, and 12 hours 50 minutes coming back. Takes longer coming back because it's against the predominant wind direction.
Flights coming back HK to Gatwick depart at 1am (ouch). But at least it's a direct flight.
ANYWAY...
Oasis Hong Kong Airlines operates directly out of Hong Kong as their headquarters. Although they advertise themselves as a budget airline, they only fly between HK and London (Gatwick), or HK and Vancouver (Canada). Their website is pretty clear and easy to use. According to their own website info (follow the menu on the left here), they reckon the flight will be 11 hours 50 minutes getting out there, and 12 hours 50 minutes coming back. Takes longer coming back because it's against the predominant wind direction.
Flights coming back HK to Gatwick depart at 1am (ouch). But at least it's a direct flight.
