British defence studies concluded that Hong Kong would be extremely hard to defend in the event of a Japanese attack, but in the mid-1930s work began on improvements to defences including along the Gin Drinkers' Line.
Forskellige British Defence-undersøgelser havde allerede konkluderet, at Hongkong ville være meget svær at forsvare i tilfælde af et japansk angreb, men i midten af 1930'erne var arbejdet begyndt på nyt forsvar, herunder Gin Drinkers' Line.