A random search for departure 31May,Sun shows the flight duration for the following nonstop flghts from LHR to HKG:
01. 12hr 15min Air New Zealand Flt 38
02. 11hr 50min Qantas Airways Flt 30
03. 11hr 35min Cathay Pacific Airways Flt 252
04. 11hr 50min Cathay Pacific Airways Flt 254 / 250
05. 12hr 15min Cathay Pacific Airways Flt 256
06. 11hr 50min British Airways Flt 25
07. 12hr 00min British Airways Flt 27
08. 12hr 15min Virgin Atlantic Flt 238
09. 12hr 20min Virgin Atlantic Flt 200