Singapore strategy

After the First World War, the Imperial German Navy's High Seas Fleet that had challenged the Royal Navy for supremacy was scuttled in Scapa Flow, but the Royal Navy was already facing serious challenges to its position as the world's most powerful fleet from the United States Navy and the Imperial Japanese Navy.[3] The United States' determination to create what Admiral of the Navy George Dewey called "a navy second to none" presaged a new maritime arms race.[4]

The British Empire in 1921. Australia, Canada, New Zealand, and South Africa were self-governing dominions.

The U.S. Navy was smaller than the Royal Navy in 1919, but ships laid down under its wartime construction program were still being launched, and their more recent construction gave the American ships a technological edge.[5] The "two-power standard" of 1889 called for a Royal Navy strong enough to take on any two other powers. In 1909, this was scaled back to a policy of 60% superiority in dreadnoughts.[6] Rising tensions over the U.S. Navy's building program led to heated arguments between the First Sea Lord, Admiral Sir Rosslyn Wemyss, and the Chief of Naval Operations Admiral William S. Benson in March and April 1919,[7] although, as far back as 1909, the government directed that the United States was not to be regarded as a potential enemy. This decision was reaffirmed by Cabinet in August 1919 in order to preclude the U.S. Navy's building program from becoming a justification for the Admiralty initiating one of its own.[8] In 1920, the First Lord of the Admiralty Sir Walter Long announced a "one-power standard", under which the policy was to maintain a navy "not ... inferior in strength to the Navy of any other power".[6] The one-power standard became official when it was publicly announced at the 1921 Imperial Conference.[9] The Washington Naval Treaty of 1922 reinforced this policy.

The Prime Ministers of the United Kingdom and the Dominions met at the 1921 Imperial Conference to determine a unified international policy, particularly the relationship with the United States and Japan.[10] The most urgent issue was that of whether or not to renew the Anglo-Japanese Alliance, which was due to expire on 13 July 1921.[11] On one side were the Prime Minister of Australia Billy Hughes and the Prime Minister of New Zealand Bill Massey, who strongly favoured its renewal.[12] Neither wanted their countries to be caught up in a war between the United States and Japan, and contrasted the generous assistance that Japan rendered during the First World War with the United States' disengagement from international affairs in its aftermath.[13] "The British Empire", declared Hughes, "must have a reliable friend in the Pacific".[14] They were opposed by the Prime Minister of Canada, Arthur Meighen, on the grounds that the alliance would adversely affect the relationship with the United States, which Canada depended upon for its security.[15] As a result, no decision to renew was reached, and the alliance was allowed to expire.[16]

The Washington Naval Treaty in 1922 provided for a 5:5:3 ratio of capital ships of the British, United States and Japanese navies.[17] Throughout the 1920s, the Royal Navy remained the world's largest navy, with a comfortable margin of superiority over Japan, which was regarded as the most likely adversary.[18] The Washington Naval Treaty also prohibited the fortification of islands in the Pacific, but Singapore was specifically excluded.[17] The provisions of the London Naval Treaty of 1930, however, restricted naval construction, resulting in a serious decline in the British shipbuilding industry.[19] Germany's willingness to limit the size of its navy led to the Anglo-German Naval Agreement of 1935. This was seen as signalling a sincere desire to avoid conflict with Britain.[20] In 1934, the First Sea Lord, Admiral Sir Ernle Chatfield, began to press for a new naval build-up sufficient to fight both Japan and the strongest European power. He intended to accelerate construction to the maximum capacity of the shipyards,[21] but the Treasury soon became alarmed at the potential cost of the program, which was costed at between £88 and £104 million.[22] By 1938, the Treasury was losing its fight to stop rearmament; politicians and the public were more afraid of being caught unprepared for war with Germany and Japan than of a major financial crisis in the more distant future.[23]

The troopship RMS Queen Mary in Singapore Graving Dock, August 1940

The Singapore strategy was a series of war plans that evolved over a twenty-year period in which the basing of a fleet at Singapore was a common but not a defining aspect. Plans were crafted for different contingencies, both defensive and offensive. Some were designed to defeat Japan, while others were merely to deter aggression.[24]

In November 1918, the Australian Minister for the Navy, Sir Joseph Cook, had asked Admiral Lord Jellicoe to draw up a scheme for the Empire's naval defence. Jellicoe set out on a tour of the Empire in the battlecruiser HMS New Zealand in February 1919.[25] He presented his report to the Australian government in August 1919. In a section of the report classified as secret, he advised that the interests of the British Empire and Japan would inevitably clash. He called for the creation of a British Pacific Fleet strong enough to counter the Imperial Japanese Navy, which he believed would require 8 battleships, 8 battlecruisers, 4 aircraft carriers, 10 cruisers, 40 destroyers, 36 submarines and supporting auxiliaries.[5]

Although he did not specify a location, Jellicoe noted that the fleet would require a major dockyard somewhere in the Far East. A paper entitled "The Naval Situation in the Far East" was considered by the Committee of Imperial Defence in October 1919. In this paper the naval staff pointed out that maintaining the Anglo-Japanese Alliance might lead to war between the British Empire and the United States. In 1920, the Admiralty issued War Memorandum (Eastern) 1920, a series of instructions in the event of a war with Japan. In it, the defence of Singapore was described as "absolutely essential".[5] The strategy was presented to the Dominions at the 1923 Imperial Conference.[26]

The authors of War Memorandum (Eastern) 1920 divided a war with Japan into three phases. In the first phase, the garrison of Singapore would defend the fortress while the fleet made its way from home waters to Singapore. Next, the fleet would sail from Singapore and relieve or recapture Hong Kong. The final phase would see the fleet blockade Japan and force it to accept terms.[27]

Most planning focused on the first phase, which was seen as the most critical. This phase involved construction of defence works for Singapore. For the second phase, a naval base capable of supporting a fleet was required. While the United States had constructed a graving dock capable of taking battleships at Pearl Harbor between 1909 and 1919, the Royal Navy had no such base east of Malta.[5] In April 1919, the Plans Division of the Admiralty produced a paper which examined possible locations for a naval base in the Pacific in case of a war with the United States or Japan. Hong Kong was considered but regarded as too vulnerable, while Sydney was regarded as secure but too far from Japan. Singapore emerged as the best compromise location.[25]

War Memorandum (Eastern), The Route to the East

The estimate of how long it would take for the fleet to reach Singapore after the outbreak of hostilities varied. It had to include the time required to assemble the fleet, prepare and provision its ships, and then sally to Singapore. Initially, the estimate was 42 days, assuming reasonable advance warning. In 1938, it was increased to 70 days, with 14 more for reprovisioning. It was further increased in June 1939 to 90 days plus 15 for reprovisioning, and finally, in September 1939, to 180 days.[28]

To facilitate this movement, a series of oil storage facilities were constructed at Gibraltar, Malta, Port Said, Port Sudan, Aden, Colombo, Trincomalee, Rangoon, Singapore, and Hong Kong.[29] A complicating factor was that the battleships could not traverse the Suez Canal fully laden, so they would have to refuel on the other side.[30] Singapore was to have storage for 1,250,000 long tons (1,270,000 t) of oil.[31] Secret bases were established at Kamaran Bay, Addu Atoll and Nancowry.[32] It was estimated that the fleet would require 110,000 long tons (110,000 t) of oil per month, which would be transported in 60 tankers.[33] Oil would be shipped in from the refineries at Abadan and Rangoon, supplemented by buying up the entire output of the Netherlands East Indies.[34]

The third phase received the least consideration, but naval planners were aware that Singapore was too far from Japan to provide an adequate base for operations close to Japan. Moreover, the further the fleet proceeded from Singapore, the weaker it would become.[27] If American assistance was forthcoming, there was the prospect of Manila being used as a forward base.[35] The idea of invading Japan and fighting its armies on its own soil was rejected as impractical, but the British planners did not expect that the Japanese would willingly fight a decisive naval battle against the odds. They were therefore drawn to the concept of a blockade. From personal experience they were aware of the impact it could have on an island nation at the heart of a maritime empire, and felt that economic pressure would suffice.[27]

A British warship inside the Admiralty IX floating dry dock at Singapore Naval Base in September 1941

Japan's vulnerability to blockade was studied. Using information supplied by the Board of Trade and the naval attaché in Tokyo, the planners estimated that the British Empire accounted for around 27 per cent of Japan's imports. In most cases these imports could be replaced from sources in China and the United States. However, certain critical materials for which Japan relied heavily on imports were identified, including metals, machinery, chemicals, oil and rubber,[36] and many of the best sources of these were under British control. Japan's access to neutral shipping could be restricted by refusing insurance to ships trading with Japan, and chartering ships to reduce the number available.[37]

The problem with enforcing a close blockade with ships was that warships loitering off the coast of Japan would be vulnerable to attack by aircraft and submarines.[38] Blockading Japanese ports with small ships was a possibility, but this would first require the destruction or neutralisation of the Japanese fleet, and it was far from certain that the Japanese fleet would place itself in a position where it could be destroyed. A plan was adopted for a more distant blockade, whereby ships bound for Japan would be intercepted as they passed through the East Indies or the Panama Canal. This would not cut off Japan's trade with China or Korea, and probably not with the United States either. The effectiveness of such a blockade was therefore questionable.[36]

Rear Admiral Sir Herbert Richmond, the Commander in Chief, East Indies Station, noted that the logic was suspiciously circular:

• We are going to force Japan to surrender by cutting off her essential supplies.
• We cannot cut off her essential supplies until we defeat her fleet.
• We cannot defeat her fleet if it will not come out to fight.
• We shall force it to come out to fight by cutting off her essential supplies.[39]

The 1919 plans incorporated a Mobile Naval Base Defence Organisation (MNBDO) which could develop and defend a forward base.[40] The MNBDO had a strength of 7,000 and included a brigade of antiaircraft artillery, a brigade of coastal artillery and a battalion of infantry, all drawn from the Royal Marines.[41] In one paper exercise, the Royal Marines occupied Nakagusuku Bay unopposed and the MNBDO developed a major base there from which the fleet blockaded Japan. Actual fleet exercises were conducted in the Mediterranean in the 1920s to test the MNBDO concept.[42] However, the Royal Marines were not greatly interested in amphibious warfare, and lacking organisational backing, the techniques and tactics of amphibious warfare began to atrophy. By the 1930s the Admiralty was concerned that the United States and Japan were well ahead of Britain in this field and persuaded the Army and RAF to join with it in establishing the Inter-Service Training and Development Centre, which opened in July 1938. Under its first commandant, Captain Loben Edward Harold Maund, it began investigating the problems of amphibious warfare, including the design of landing craft.[43]

Nor was this the only field in which the Royal Navy was lagging in the 1930s. In the 1920s, Colonel the Master of Sempill led the semi-official Sempill Mission to Japan to help the Imperial Japanese Navy establish an air arm.[44] At the time the Royal Navy was the world leader in naval aviation. The Sempill mission taught advanced techniques such as carrier deck landing, conducted training with modern aircraft, and provided engines, ordnance and technical equipment.[45] Within a decade, Japan had overtaken Britain.[46] The Royal Navy pioneered the armoured flight deck, which enabled carriers to absorb damage, but resulted in limiting the number of aircraft that a carrier could operate.[47] The Royal Navy had great faith in the ability of ships' antiaircraft batteries, and so saw little need for high performance fighters.[48] To maximise the benefit of the small numbers of aircraft that could be carried, the Royal Navy developed multi-role aircraft such as the Blackburn Roc, Fairey Fulmar, Fairey Barracuda, Blackburn Skua and Fairey Swordfish. As a result, the Royal Navy's aircraft were no match for their Japanese counterparts.[49]

The possibility of Japan taking advantage of a war in Europe was foreseen. In June 1939, the Tientsin Incident demonstrated another possibility: that Germany might attempt to take advantage of a war in the Far East.[50] In the event of a worst-case scenario of simultaneous war with Germany, Italy and Japan, two approaches were considered. The first was to reduce the war to one against Germany and Japan only by knocking Italy out of the conflict as quickly as possible.[51] The former First Sea Lord, Sir Reginald Drax, who was brought out of retirement to advise on strategy, called for a "flying squadron" of four or five battleships, along with an aircraft carrier, some cruisers and destroyers, to be sent to Singapore. Such a force would be too small to fight the Japanese main fleet, but could protect British trade in the Indian Ocean against commerce raiders. Drax argued that a small, fast force would be better in this role than a large, slow one. When more ships became available, it could become the nucleus of a full-sized battle fleet. Chatfield, now Minister for Coordination of Defence, disagreed with this concept. He felt that the flying squadron would become nothing more than a target for the Japanese fleet. Instead, he put forward a second approach, namely that the Mediterranean be abandoned and the fleet sent to Singapore.[52]

One of Singapore's 15-inch coastal defence guns elevated for firing

Following surveys, a site at Sembawang was chosen for a naval base.[53] The Straits Settlements made a free gift of 2,845 acres (1,151 ha) of land for the site,[54] and a sum of £250,000 for construction of the base was donated by Hong Kong in 1925. That exceeded the United Kingdom's contribution that year of £204,000 towards the floating dock.[55] Another £2,000,000 was paid by the Federated Malay States, while New Zealand donated another £1,000,000.[56] The contract for construction of the naval dockyard was awarded to the lowest bidder, Sir John Jackson Limited, for £3,700,000.[57] Some 6,000,000 cubic yards (4,600,000 m³) of earth were moved to level the ground, and 8,000,000 cubic yards (6,100,000 m³) of marsh was filled in. The floating dock was constructed in England and towed to Singapore by Dutch tugboats. It was 1,000 feet (300 m) long and 1,300 feet (400 m) wide, making it one of the largest in the world. There would be 5,000 feet (1,500 m) of deep water quays, and supporting infrastructure including warehouses, workshops and hospitals.[58]

To defend the naval base, heavy 15-inch naval guns (381.0 mm) were stationed at Johore battery, Changi, and at Buona Vista to deal with battleships. Medium BL 9.2 inch guns (233.7 mm) were provided for dealing with smaller attackers. Batteries of smaller calibre anti-aircraft guns and guns for dealing with raids were located at Fort Siloso, Fort Canning and Labrador.[59] The five 15-inch guns were all surplus Navy guns, manufactured between 1903 and 1919.[60] Part of their cost was met from a gift of £500,000 from Sultan Ibrahim of Johor for the Silver Jubilee of the coronation King George V. Three of the guns were given an all-round (360°) traverse and subterranean magazines.[61]

Aviation was not neglected. Plans called for an air force of 18 flying boats, 18 reconnaissance fighters, 18 torpedo bombers and 18 single-seat fighters to protect them. Royal Air Force airfields were established at RAF Tengah and RAF Sembawang.[62] The Chief of the Air Staff, Air Marshal Lord Trenchard, argued that 30 torpedo bombers could replace the 15-inch guns. The First Sea Lord, Admiral of the Fleet Lord Beatty, did not agree. A compromise was reached whereby the guns would be installed, but the issue was reconsidered when better torpedo planes became available.[63] Test firings of 15-inch and 9.2-inch guns at Malta and Portsmouth in 1926 indicated that greatly improved shells were required if the guns were to have a chance of hitting a battleship.[64]

The King George VI dry dock was formally opened by the Governor of the Straits Settlements, Sir Shenton Thomas, on 14 February 1938. Two squadrons of the Fleet Air Arm provided a flypast. The 42 vessels in attendance included three US Navy cruisers. The presence of this fleet gave an opportunity to conduct a series of naval, air and military exercises. The aircraft carrier HMS Eagle was able to sail undetected to within 135 miles (217 km) of Singapore and launch a series of surprise raids on the RAF airfields. The local air commander, Air Vice-Marshal Arthur Tedder, was greatly embarrassed. The local land commander, Major-General Sir William Dobbie, was no less disappointed by the performance of the anti-aircraft defences. Reports recommended the installation of radar on the island, but this was not done until 1941. The naval defences worked better, but a landing party from HMS Norfolk was still able to capture the Raffles Hotel. What most concerned Dobbie and Tedder was the possibility of the fleet being bypassed entirely by an overland invasion of Malaya from Thailand. Dobbie conducted an exercise in southern Malaya which demonstrated that the jungle was far from impassable. The Chiefs of Staff Committee concluded that the Japanese would most likely land on the east coast of Malaya and advance on Singapore from the north.[65]

In Australia the conservative Nationalist Party government of Stanley Bruce latched onto the Singapore strategy, which called for reliance on the British navy, supported by a naval squadron as strong as Australia could afford. Between 1923 and 1929, £20,000,000 was spent on the Royal Australian Navy (RAN), while the Australian Army and the munitions industry received only £10,000,000 and the fledgling Royal Australian Air Force (RAAF) just £2,400,000.[66] The policy had the advantage of pushing responsibility for Australian defence onto Britain. Unlike New Zealand, Australia declined to contribute to the cost of the base at Singapore.[67] In petitioning a parsimonious government for more funds, the Australian Army had to refute the Singapore strategy, "an apparently well-argued and well-founded strategic doctrine that had been endorsed at the highest levels of imperial decision-making".[68]

Troops of the ill-fated Australian 8th Division disembark at Singapore Harbour 15 August 1941.

An alternative policy was put forward in 1923 by the Australian Labor Party, which was in opposition for all but two years of the 1920s and 1930s. It called for Australia's first line of defence to be a powerful air arm, supported by a well-equipped Australian Army that could be rapidly expanded to meet an invasion threat. This, in turn, required a strong munitions industry. Labor politicians cited critics like Rear Admiral William Freeland Fullam, who drew attention to the vulnerability of warships to aircraft, naval mines and submarines. The Labor Party's Albert Green noted in 1923 that when a battleship of the day cost £7,000,000 while an aircraft cost £2,500, there was a genuine cause for concern as to whether the battleship was a better investment than hundreds of aircraft, if the aircraft could sink battleships.[69] The Labor Party's policy became indistinguishable from the Army's position.[66]

In September 1926, Lieutenant Colonel Henry Wynter gave a lecture to the United Services Institute of Victoria entitled "The Strategical Inter-relationship of the Navy, the Army and the Air Force: an Australian View", which was published in the April 1927 edition of British Army Quarterly. In this article Wynter argued that war was most likely to break out in the Pacific at a time when Britain was involved in a crisis in Europe, which would prevent Britain from sending sufficient resources to Singapore. He contended that Singapore was vulnerable, especially to attack from the land and the air, and argued for a more balanced policy of building up the Army and RAAF rather than relying on the RAN.[66] "Henceforward", wrote Australian official historian Lionel Wigmore, "the attitude of the leading thinkers in the Australian Army towards British assurances that an adequate fleet would be sent to Singapore at the critical time was (bluntly stated): 'We do not doubt that you are sincere in your beliefs but, frankly, we do not think you will be able to do it.'"[70]

Frederick Shedden wrote a paper putting the case for the Singapore strategy as a means of defending Australia. He argued that since Australia was also an island nation, it followed that it would also be vulnerable to a naval blockade. If Australia could be defeated without an invasion, the defence of Australia had to be a naval one. Colonel John Lavarack, who had attended the Imperial Defence College class of 1928 with Shedden, disagreed. Lavarack responded that the vast coastline of Australia would make a naval blockade very difficult, and its considerable internal resources meant that it could resist economic pressure.[71] When Richmond attacked the Labor Party's position in an article in British Army Quarterly in 1933, Lavarack wrote a rebuttal.[72] In 1936, the leader of the opposition John Curtin read an article by Wynter in the House of Representatives. Wynter's outspoken criticism of the Singapore strategy led to his transfer to a junior post.[72] Soon after the outbreak of war with Germany on 3 September 1939,[73] Prime Minister Robert Menzies appointed a British officer, Lieutenant General Ernest Squires, to replace Lavarack as Chief of the General Staff. Within months, the Chief of the Air Staff was replaced with a British officer as well.[74]

Successive New Zealand governments—the Reform Government of 1912–1928, United Government in 1928–1931, United-Reform Coalition Government of 1931–1935, and the First Labour Government in 1935–1949—all supported the Singapore Strategy. The New Zealand financial contribution was eight annual payments of £125,000, a million pounds in total,[75] rather than the £225,000 annually proposed by the Admiralty.[76] Expansion of the New Zealand Devonport Naval Base was also proposed, and in 1926 the alternative of a third cruiser was considered. Labour, on coming to power in 1935, gave more importance to a local air force,[77] though later Walter Nash accepted the need to keep sea lanes open.[78] There was little liaison with Australia; in 1938 New Zealand Chiefs of Staff papers were sent to London but not Australia.[79] But by 1936 New Zealand military confidence in the Singapore Strategy was waning; with the possibility of Italy as well as Germany and Japan as enemies, in seemed likely that Britain would also be committed in the Mediterranean.[80]

HMS Prince of Wales leaves Singapore on 8 December 1941

With war with Germany now a reality, Menzies sent Richard Casey to London to seek reassurances about the defence of Australia in the event that Australian forces were sent to Europe or the Middle East.[81] In November 1939, Australia and New Zealand were given reassurances that Singapore would not be allowed to fall, and that in the event of war with Japan, the defence of the Far East would take priority over the Mediterranean.[82] This seemed possible as the Kriegsmarine, the German navy, was relatively small and France was an ally.[50] Bruce, now Australian High Commissioner to the United Kingdom, and Casey met with British Cabinet ministers on 20 November and left with the impression that, despite the reassurances, the Royal Navy was not strong enough to deal with simultaneous crises in Europe, the Mediterranean and the Far East.[83]

During 1940, the situation slowly but inexorably slid towards a worst-case scenario. In June, Italy joined the war on Germany's side and France was knocked out.[84] The Chiefs of Staff Committee now reported:

The security of our imperial interests in the Far East lies ultimately in our ability to control sea communications in the south-western Pacific, for which purpose adequate fleet must be based at Singapore. Since our previous assurances in this respect, however, the whole strategic situation has been radically altered by the French defeat. The result of this has been to alter the whole of the balance of naval strength in home waters. Formerly we were prepared to abandon the Eastern Mediterranean and dispatch a fleet to the Far East, relying on the French fleet in the Western Mediterranean to contain the Italian fleet. Now if we move the Mediterranean fleet to the Far East there is nothing to contain the Italian fleet, which will be free to operate in the Atlantic or reinforce the German fleet in home waters, using bases in north-west France. We must therefore retain in European waters sufficient naval forces to watch both the German and Italian fleets, and we cannot do this and send a fleet to the Far East. In the meantime the strategic importance to us of the Far East both for Empire security and to enable us to defeat the enemy by control of essential commodities at the source has been increased.[85]

There remained the prospect of American assistance. In secret talks in Washington, D.C., in June 1939, Chief of Naval Operations Admiral William D. Leahy raised the possibility of an American fleet being sent to Singapore.[86] In April 1940, the American naval attaché in London, Captain Alan Kirk, approached the Vice Chief of the Naval Staff, Vice-Admiral Sir Thomas Phillips, to ask if, in the event of the United States Fleet being sent to the Far East, the docking facilities at Singapore could be made available, as those at Subic Bay were inadequate. He received full assurances that they would be.[87] Hopes for American assistance were dashed at the staff conference in Washington, D.C., in February 1941. The U.S. Navy was primarily focused on the Atlantic. The American chiefs envisaged relieving British warships in the Atlantic and Mediterranean so a British fleet could be sent to the Far East.[88]

HMS Repulse leaves Singapore on 8 December 1941

In July 1941, the Japanese occupied Cam Ranh Bay, which the British fleet had hoped to use on its northward drive. This put the Japanese uncomfortably close to Singapore.[89] As diplomatic relations with Japan worsened, in August 1941, the Admiralty and the Chiefs of Staff began considering what ships could be sent. The Chiefs of Staff decided to recommend sending HMS Barham to the Far East from the Mediterranean, followed by four Revenge-class battleships that were refitting at home and in the United States, but Barham was sunk by a German U-boat in November 1941. Three weeks later the remaining two battleships at Alexandria, HMS Queen Elizabeth and Valiant were seriously damaged by Italian human torpedoes. While no more destroyers or cruisers were available, the Admiralty decided that an aircraft carrier, the small HMS Eagle could be sent.[90]

Winston Churchill, now the Prime Minister, noted that since the German battleship Tirpitz was tying up a superior British fleet, a small British fleet at Singapore might have a similar disproportionate effect on the Japanese. The Foreign Office expressed the opinion that the presence of modern battleships at Singapore might deter Japan from entering the war.[91] In October 1941, the Admiralty therefore ordered HMS Prince of Wales to depart for Singapore, where it would be joined by HMS Repulse.[90] The carrier HMS Indomitable was to join them, but it ran aground off Jamaica on 3 November, and no other carrier was available.[92]

In August 1940, the Chiefs of Staff Committee reported that the force necessary to hold Malaya and Singapore in the absence of a fleet was 336 first-line aircraft and a garrison of nine brigades. Churchill then sent reassurances to the prime ministers of Australia and New Zealand that, if they were attacked, their defence would be a priority second only to that of the British Isles.[93] A defence conference was held in Singapore in October 1940. Representatives from all three services attended, including Vice-Admiral Sir Geoffrey Layton (Commander in Chief, China Station); the General Officer Commanding Malaya Command, Lieutenant General Lionel Bond; and Air Officer Commanding the RAF in the Far East, Air Marshal John Tremayne Babington. Australia was represented by its three deputy service chiefs, Captain Joseph Burnett, Major General John Northcott and Air Commodore William Bostock. Over ten days, they discussed the situation in the Far East. They estimated that the air defence of Burma and Malaya would require a minimum of 582 aircraft.[94] By 7 December 1941, there were only 164 first-line aircraft on hand in Malaya and Singapore, and all the fighters were the obsolete Brewster F2A Buffalo.[95] The land forces situation was not much better. There were only 31 battalions of infantry of the 48 required, and instead of two tank regiments, there were no tanks at all. Moreover, many of the units on hand were poorly trained and equipped. Yet during 1941 Britain had sent 676 aircraft and 446 tanks to the Soviet Union.[96]

The Japanese were aware of the state of the Singapore defences. There were spies in Singapore, such as Captain Patrick Heenan, and a copy of the Chiefs of Staff's August 1940 appreciation was among the secret documents captured by the German surface raider Atlantis from the SS Automedon on 11 November 1940. The report was handed over to the Japanese, and the detailed knowledge of Singapore's defences thus obtained may have encouraged the Japanese to attack.[97]

On 8 December 1941, the Japanese occupied the Shanghai International Settlement. A couple of hours later, landings began at Kota Bharu in Malaya. An hour after that, the Imperial Japanese Navy attacked Pearl Harbor.[98] On 10 December, Prince of Wales and Repulse, sailing to meet the Malaya invasion force, were sunk by Japanese air attack.[99] After the disastrous Malayan Campaign, Singapore surrendered on 15 February 1942.[100] During the final stages of the campaign, the 15-inch and 9.2-inch guns had bombarded targets at Johor Bahru, RAF Tengah and Bukit Timah.[101]

• Singapore Naval Base
• War Plan Orange