representative, Tamara, and Phibun on 2 December. Phibun was prepared to look the other way if Japan invaded the Kra Peninsula, but wanted them to avoid passing through the Bangkok Plain. After further discussions on 3 December, Phibun agreed to passage through Thailand, provided Thailand could regain the territories ceded in the Anglo-Siamese Treaty of 1909, as well as Burma's Shan State. On 2 December, the Japanese military issued the order "Climb Mount Niitaka", which set in motion the war in the Pacific. The main invasion fleet for Operation "E", the invasion of Malaya and Thailand, sailed from Sanya, Hainan Island, China on 4 December. Further troops and ships joined the fleet from Cam Ranh Bay, Indochina. While the Japanese were preparing, the British and Americans were formulating their response to the Japanese troop buildup and the potential invasion of Thailand. Phibun, on the same day he reached an agreement with the Japanese, was advised by the British that Thailand was about to be invaded by the Japanese. At noon on 6 December, one of three RAAF No 1 Squadron Lockheed Hudsons on a reconnaissance flight over the South China Sea, located three Japanese ships steaming west, and about 15 minutes later, sighted the IJN Southern Expeditionary Fleet convoy, consisting of a battleship, five cruisers, seven destroyers and 22 transports. One of the two merchant seaplane tenders with the convoy, the Kamikawa Maru, launched a Mitsubishi F1M "Pete" floatplane to intercept the Hudson, which eluded it by taking cover in the clouds. A few minutes later, a second Hudson also sighted the convoy. Air Chief Marshal Sir Robert Brooke-Popham was advised of the sightings at 14:00. He was not authorised to take any action against the convoy, as Britain was not at war with Japan, the Japanese intentions were still unclear, and no aggressive action had yet been taken against British or Thai territory. He put his forces in Malaya on full alert and ordered continued surveillance of the convoy. On 7 December at 03:00, Vice-Admiral Jisaburō Ozawa ordered patrols in the area between the convoy and Malaya. The convoy was about from Kota Bharu. There was heavy rain and zero visibility. The Kamikawa Maru and Sagara Maru launched 11 F1M2's and six Aichi E13A's. About west northwest of Panjang Island at 08:20, an E13A1 ZI-26 from the Kamikawa Maru, piloted by Ensign Ogata Eiichi, spotted a No. 205 Squadron