The 8th Division was raised to fight Nazi Germany, and was trained for the conditions of the Middle East. In December 1940, the 24th Brigade was sent to North Africa, and became part of the 9th Division. It was replaced in the 8th Division by the 27th Brigade.
However, as the possibility of war with Japan loomed, the 22nd Brigade was sent instead to Malaya on February 2, 1941. The 23rd Brigade moved to Darwin in April. The 2/22nd Battalion was detached from it and deployed to Rabaul, New Britain in April. The 27th Brigade joined the 22nd Brigade in Malaya, in August. The remainder of the 23rd Brigade was split into another two detachments: the 2/40th Battalion left for Timor, on December 12 and; the 2/21st Battalion went to Ambon in the Dutch East Indies on December 17. The 23rd Brigade headquarters remained in Darwin.
On January 14, parts of the division went into action south of Kuala Lumpur, at Gemas and Muar. The 2/30th Battalion had some early success at the Gemencheh River Bridge, destroying a Japanese battalion. However, other Allied units were already severely depleted and demoralised, and Japanese flanking operations began to take their toll, whose tactics of isolation and encirclement often forced masssurrenders of other Allied units.As war broke out Japanese forces based in Vichy French-controlled Indochina quickly overran Thailand and invaded Malaya. The demoralising loss of two British capital ships, HMS Repulse and HMS Prince of Wales, off Malaya on December 10, 1941, neutralised Allied naval superiority, allowing the Japanese to perform amphibious assaults on the Malayan coast with much less resistance. Japanese forces met stiff resistance from III Corps of the Indian Army and British units in northern Malaya, but Japan's superiority in air power, tanks andinfantry tactics forced the Allied units, who had very few tanks and remained vulnerable to isolation and encirclement, back.
The 2/29th and the 2/19th Battalions were detached as reinforcements for the Indian 45th Brigade, which was in danger of being overrun near the Muar River. By January 22, a mixed force from the two battalions, with some Indian troops, had been isolated and overrun. Members of the Japanese Imperial Guards Division massacred about 150 Allied prisoners at Parit Sulong, following the fighting. Lieutenant-ColonelCharles Anderson, acting commander of the 2/19th, was taken prisoner and was later awarded the Victoria Cross for his actions.
The remainder of the 27th Brigade was waging a rearguard action, while the rest of the 22nd Brigade had been sent back to guard the north end of the Johor-Singapore Causewaywhich linked the Malayan Peninisula to Singapore, as Allied forces retreated.
By January 31, the last Allied forces had left Malaya, and Allied engineers blew a hole 70 feet (21 m) wide in the causeway.As Allied forces in Malaya retreated towards Singapore, a 2,000-strong detachment of 8th Division reinforcements arrived in Singapore, including the 2/4th Machine Gun Regiment.
The Allied commander, Lieutenant General Arthur Percival gave Major General Gordon Bennett's 8th Division the task of defending the prime invasion points on the north side of the island, in a terrain dominated by mangrove swamps and forest. The 22nd Brigade was assigned a daunting 10-mile (16 km) wide sector in the west of the island, and the 27th Brigade a 4,000-yard (3,700 m) zone in the north west, near the causeway.
From vantage points across the straits, including the Sultan of Johore's palace, as well as aerial reconnaissance and infiltrators, the Japanese commander, General Tomoyuki Yamashita and his staff gained excellent knowledge of the Allied positions. From February 3, the Australian positions were shelled by Japanese artillery. Shelling and air attacks intensified over the next five days, destroying communications between Allied units and their commanders.
At 8.30pm on February 8, Australian machine gunners opened fire on vessels carrying a first wave of 4,000 Japanese troops towards Singapore Island.
Fierce fighting raged all day, but eventually the increasing Japanese numbers, as well as their artillery, planes and military intelligence began to exploit gaps in the Australian lines. By midnight the two 8th Division infantry brigades were separated and isolated, and the 22nd Brigade was being forced to retreat. At 1 am, further Japanese troops were landed in the west of the island and the last Australian reserves went into position.
Towards dawn on the February 9, elements of the 22nd Brigade were being overrun and it was decided to form a secondary defensive line. The 2/18th Battalion had lost more than 50% of its personnel. During the course of the day, the 22nd and other Allied units in the east were forced to retreat further south.
The 27th Brigade had not yet faced an attack. However, the next day, the Japanese Imperial Guard made a botched landing in the north west, suffering severe casualties from drowning and burning oil in the water, as well as Australian mortars and machine guns. In spite of the 27th Brigade's success, as a result of a misunderstanding, they began to withdraw from Kranji in the north. That same day, further misunderstandings, increasing numbers of desertions and the arrival of Japanese tanks, caused the Allies to lose control of the crucial Kranji-Jurong ridge through the western side of the island. However the Japanese armoured units failed to seize an opportunity to advance into the heart of the city itself.
On February 11, knowing that his own supplies were running low, Yamashita called on Percival to "give up this meaniningless and desperate resistance".
The next day the Allied lines stabilised around a small area on the south side of the island and fought off determined Japanese assaults. However, the Allies lost more ground on February 13, and Bennett and other senior officers advised Percival to surrender, in the interests of minimising civilian casualties. Percival refused but unsuccessfully sought authority to surrender from his superiors.
The following day the remaining Allied units battled on; civilian casualties mounted as one million people crowded into the area now held by the Allies and bombing and artillery attacks intensified. Civilian authorities began to fear that the water supply would soon give out. Japanese troops killed 200 staff and patients after they captured Alexandra Barracks Hospital.
By the morning of February 15, the Japanese had broken through the last line of defence in the north and food and some kinds of ammunition had begun to run out. After meeting his unit commanders, Percival contacted the Japanese and formally surrendered the Allied forces to Yamashita, shortly after 5.15 pm. Bennett created an enduring controversy when he handed over the 8th Division to a brigade commander, commandeered a boat and managed to escape captivity.
Almost 15,000 Australians became prisoners of war at Singapore, an absolute majority of all Australian prisoners of the Japanese in World War II. During the Malaya-Singapore campaign as a whole, the 8th Division suffered 73% of Allied deaths in battle, even though they comprised only 14% of the Allied forces.