embassy staff; disaffected Malayans (particularly members of the Japanese-established Tortoise Society); and Japanese, Korean, and Taiwanese business people and tourists. Japanese spies, which included a British intelligence officer, Captain Patrick Stanley Vaughan Heenan, also provided intelligence and assistance. Prior to hostilities Japanese intelligence officers like Iwaichi Fujiwara had established covert intelligence offices (or Kikans) that linked up with the Malay and Indian pro-independence organisations such as Kesatuan Melayu Muda in Malaya Indian Independence League. The Japanese gave these movements financial support in return for their members providing intelligence and later assistance in determining Allied troop movements, strengths, and dispositions prior to the invasion. Through the operation of these networks prior to the invasion the Japanese knew where the Commonwealth forces were based and their unit strengths, had good maps of Malaya, and had local guides available to provide them with directions. November 1941 In November 1941 the British became aware of the large scale buildup of Japanese troops in French Indo-China. Thailand was seen to be under threat from this build-up as well as Malaya. British strategists had foreseen the possibility of Thailand's Kra isthmus being used by the Japanese to invade Malaya. To counteract this potential threat, plans for a pre-emptive invasion of southern Thailand, named Operation Matador, had been drawn up. By the time the invasion became highly likely the British decided not to use them for political reasons. Japanese invasion of Malaya The Malayan campaign began when the 25th Army, under the command of Lieutenant General Tomoyuki Yamashita, invaded Malaya on 8 December 1941. Japanese troops launched an amphibious assault on the northern coast of Malaya at Kota Bharu and started advancing down the eastern coast of Malaya. The Japanese 5th Division also landed at Pattani and Songkhla in Thailand, then moved south into western Malaya. French Indo-China was still under French administration, and had little option but to co-operate with the Japanese. The French authorities therefore submitted to the Japanese military using the territory's ports as naval bases, building air bases, and massing forces there for the invasion. Japan also coerced Thailand into co-operating with the invasion, though Thai troops resisted the landings in Thai territory for eight hours. At 04:00, 17 Japanese bombers attacked Singapore, the first ever air raid on the colony. It became evident to the British that Japanese bombers based in Indochina were now within range of Singapore. The Japanese were initially