When
World War II broke out in September 1939, although only 52, Bennett was passed over for command of the
Second Australian Imperial Force, the position going to General
Thomas Blamey. The Chief of the General Staff, General Sir
Brudenell White, seems to have been opposed to Bennett being given an active command. In the
Australian Dictionary of Biography (ADB), A. B. Lodge, Bennett's biographer, commented: "Because of his temperament, he was considered unsuitable for a semi-diplomatic command, and one that involved subordination to British generals. Bennett was as scathing of British officers as he was of Australian regulars." Instead, Bennett was given a command in the
Volunteer Defence Corps, the Australian version of the British
Home Guard. In July 1940, he took over command of the Eastern Command Training Depot. After White's death in the
Canberra air disaster in August 1940, Bennett was appointed commander of the newly formed
8th Division, replacing
Vernon Sturdee, who was promoted to White's former role. In February 1941, the 8th Division's headquarters, along with one of its brigades – the
22nd – was posted to
Malaya after a request from the British for Australia to contribute troops to bolster the garrison there, amid growing concerns of war with the Japanese, and as part of the plans that had been formulated as the pre-war
Singapore strategy. The
27th Brigade was also dispatched in August, but the division's third brigade, the
23rd Brigade remained in Australia. Relations between Bennett and his superiors, and also his subordinate brigade commander, Brigadier
Harold Taylor, were not good. Lodge commented: "Bennett's dealings with British senior officers, especially with the general officer commanding, Malaya, Lieutenant General
A.E. Percival, were devoid of harmony." (second right), Lieutenant-General Bennett (far right) and Allied naval officers discussing an SWPA situation map, February 1943 In December 1941, the Japanese
invasion of Malaya began. Bennett found himself in command of an ad hoc force known as "Westforce", which included the Australian 27th Brigade – but not the 22nd, which had been transferred to III Indian Corps – and several Indian units. Bennett's command was not engaged in the early stages of the fighting because the initial Japanese attacks fell on British and Indian units around
Kota Bharu and the Thai–Malay border. However, as the Japanese pushed the defenders back and advanced into
Johore, the Australians fought several actions throughout January. The most significant of those came around
Gemas and
Muar, in which the Australians experienced some local success before being forced to withdraw to Singapore at the end of the month, along with the rest of the Allied forces. On Singapore, Bennett's command once again included the two Australian brigades – the 22nd and 27th – which were allocated the task of defending the north-western sector of the island. On 8 February 1942, the Japanese launched an assault across the Johore Strait, concentrating upon the sector held by Bennett's troops. The weight fell on the 22nd Brigade's area and, trying to fend off two Japanese divisions, they were eventually forced to withdraw towards the centre of the island. The 27th Brigade initially managed to hold its sector, but it was subjected to a follow-up assault on 10 February and, as the 22nd fell back, it was also forced to withdraw. Heavy fighting followed over the next week, but eventually the Allied troops were pushed across the island to Singapore's urban areas. On 15 February, Percival began surrender negotiations with the Japanese. That night, Bennett decided that it was his duty to escape from Singapore rather than surrender. Consequently, he handed over command of the 8th Division to Brigadier
Cecil Callaghan and, with a few junior officers and some local Europeans, Bennett commandeered a sampan and crossed the
Strait of Malacca to the east coast of
Sumatra. There, they transferred to a launch in which they sailed up the
Batang Hari River, eventually proceeding by car to
Padang, on the west coast of Sumatra. From there, Bennett flew to Java and then to Australia, arriving in Melbourne on 2 March 1942. The fall of Singapore – the largest capitulation in British military history – shocked Australians, resulting in the capture of almost 15,000 Australians and many more Indian and British soldiers. Nevertheless, Bennett's escape was initially regarded as praiseworthy, at least publicly. Prime Minister
John Curtin issued a statement that read: However, within the military, particularly its senior echelons, Bennett was criticised for leaving his troops. In April 1942, he was promoted to lieutenant general and given command of
III Corps in
Perth. At the time, it was an important post but, by 1943, as the possibility of a Japanese invasion of Australia faded, it became a backwater. Bennett was told by Blamey that he would not be given another active command, and Bennett was transferred to the Reserve of Officers in May 1944. He soon published his account of the Malayan campaign,
Why Singapore Fell, which was critical of Percival and other British officers, although his opinions were later challenged by several Australian officers, including Callaghan. Blamey unsuccessfully tried to prevent the book's publication. Upon retirement from active service, Bennett began writing for a Sydney newspaper and was a correspondent for the
Australian Broadcasting Commission. He remained concerned about his soldiers, though, and met the first group of recently freed 8th Division prisoners of war when they arrived in Sydney on the transport
Manunda. For their part, the majority of his former soldiers welcomed him, and some even hung a sign over the side of the ship, which read: "We want Bennett". They later put it in his car as a gesture of their support. ==Postwar inquiries==