On 8 December 1941, the Japanese launched their attacks on Hong Kong Island. After the fall of the New Territories and Kowloon, the British Forces immediately strengthened the defences at Lei Yue Mun to prevent the Japanese from crossing the Lei Yue Mun Channel from Devil's Peak. The defence forces managed to repulse several raids by the Japanese, but were eventually overwhelmed and the fort fell into enemy hands on 19 December. The fort no longer bore any defensive significance in the post-war period and became a training ground for the British Forces until 1987, when it was finally vacated.