http://pwencycl.kgbudge.com/H/o/Hong_Kong.htm
Maltby knew the frontier was indefensible with just three battalions, and planned to make the Gin Drinker's Line (named for Gin Drinker's Bay, which anchored one end) his main line of resistance on the mainland.
38 Division was well-equipped with bridging equipment, and it took the Japanese just two days to reach the Gin Drinker's Line in spite of the demolitions. Here the British hoped to hold for some time, but the Third Battalion, 228 Regiment drove the Royal Scots out of the Shing Mun redoubt in an unauthorized night attack. In an illustration of Japanese tactical inflexibility of the kind that would prove fatal later in the war, Sakai chastised the commander of the battalion for acting without orders, and ordered the Third Battalion to retreat from Shing Mun! The order was disobeyed, and Sakai reluctantly accepted the fait accompli. However, Sakai's order did prevent Third Battalion from immediately exploiting its success, and the Royal Scots were able to reform their line along Golden Hill.
Rumors spread among the Indian troops, who themselves fought very well throughout the battle, that the Scots had broken and fled in panic from the Shing Mung redoubt. This so stung the Scots that they fought ferociously when the Japanese tried to force Golden Hill, and they counterattacked against seemingly impossible odds after being forced to retreat from the position. The counterattack was momentarily successful, but fresh Japanese troops soon took the position from the exhausted Scots for good.
The loss of Golden Hill cut the supply route for the Punjabis and Rajputs and unhinged the Gin Drinker's Line, and by 13 December the British were forced to evacuate their remaining forces to Victoria Island.
More here:
http://en.wikipedia.org/wiki/Gin_Drinkers_Line
Gin Drinkers Line (Chinese: 醉酒灣防線) or Gin Drinker's Line was a British military defence line against Japanese invasion in Hong Kong, 1941. Bunkers, concrete fortified machine gun posts, trenches and artillery batteries were built along the line. Its name came from Gin Drinkers Bay, a bay nearby in Kwai Chung, Hong Kong. With construction was started in 1936, it is linked to the several peaks between New Kowloon and New Territories.
The concept came from the Maginot Line in France. The British believed the line could protect the colony from Japanese invasion for at least six months and even called it the "Oriental Maginot Line". The Japanese generals also believed the line would stop their advance until the scouts found out the line was very weak. For example, only 30 soldiers were defending a bunker with a capacity of 120 soldiers. Similar to the Maginot Line, the Gin Drinkers Line was generally considered to be a complete failure. The line and the whole of Kowloon were abandoned by the British troops in just two days.
There are some remains of bunkers near Shing Mun Reservoir, with the defence lines named after London roads, for example, Charing Cross to provide familiarity to the soldiers of the Middlesex regiment. One of the Japanese invasion forces broke the defence line here.