The interwar years and the defence of Singapore

Read the PDF edition (4 pages)

War and mutiny

The First World War brought prosperity to Singapore through the demand for tin and rubber, while the fighting itself remained far from the colony. Its most serious local event was the mutiny of part of the 5th Light Infantry, a regiment of the Indian Army, which broke out on 15 February 1915. The mutineers killed 36 soldiers and civilians before the revolt was suppressed with the help of landing parties from French, Russian and Japanese warships. After courts martial, 47 mutineers were publicly executed at Outram Prison.¹

The episode exposed the vulnerability of the colony. In 1915 Britain relied on Japanese warships, then allies under the Anglo-Japanese Alliance of 1902, to help restore order in its most important port in Southeast Asia. After the war, that alliance came to an end. The Four-Power Treaty concluded at the Washington Conference made it defunct in December 1921, and it formally terminated on 17 August 1923.² Japan, which had been an ally, now appeared as the most likely naval adversary in the Pacific.

The choice of Singapore

The British response was the so-called Singapore strategy. Britain could not afford to keep a battle fleet permanently in Asia. It planned instead to build a fortified base at Singapore to which the main fleet would sail from European waters in an emergency. Singapore was chosen in 1919 as the location of the base. The Washington Naval Treaty of 1922 fixed a ratio of 5:5:3 for the capital ships of Britain, the United States and Japan and barred new fortifications on the islands of the Pacific, a restriction that did not extend to Singapore.³

The strategy reflected the logic of the coaling station on a larger scale. A battle fleet operating in Asian waters needed a dock large enough to repair its biggest ships, stores of fuel oil, ammunition and workshops. Hong Kong was too close to Japan and too small. Singapore offered deep water, a central position between the Indian Ocean and the Pacific and a stable colonial administration. Its value to the navy derived from the same geography that made it valuable to merchants.

Building the base at Sembawang

The naval base scheme was announced in 1923. Its construction proceeded slowly, delayed by debates over cost and by changes of government in London. The Straits Settlements gave 2,845 acres of land at Sembawang in May 1923, valued at about £150,000. Other parts of the empire contributed: Hong Kong gave £250,000 and the Federated Malay States £2 million in mid-1926. In April 1927 New Zealand committed £1 million, to be paid over eight years. In 1928 the contract for the main works went to Sir John Jackson Ltd for £3.7 million. The works employed about 5,000 workers and 100 British staff, who used 1.6 million tons of granite from Johor.⁴

The centrepiece of the base, the King George VI graving dock, was formally opened by the Governor, Sir Shenton Thomas, on 14 February 1938, in the presence of 42 vessels, including three cruisers of the United States Navy.⁵ At more than 300 metres it was the largest dry dock in the world at the time. The base became known as the “Gibraltar of the East”, a phrase attributed to Churchill. The sources diverge on the total cost. One gives £60 million for the base, while the general history of Singapore gives 500 million dollars on completion in 1939.⁶ The figures are not directly comparable, since they use different currencies and probably different definitions of what the base included.

An economy of defence

The base was the largest public works project in the history of the colony. It brought construction contracts, employment and imperial spending to Singapore during the depression of the early 1930s, when the price of rubber and tin collapsed. It also tied the economy of the colony more closely to British military expenditure, a dependence that would become an economic problem when Britain later decided to withdraw its forces, as Chapter III of Part C shows.

The air age arrived at the same time. Kallang Airport, the first purpose-built civil international airport in Singapore, was opened on 12 June 1937 by Sir Shenton Thomas.⁷ Aviation added a new dimension to Singapore’s connectivity, which Changi would later carry much further.

Closing the gates: immigration restriction

The depression also changed migration policy. With unemployment rising, the colonial government restricted the entry of unskilled male labour. The sources differ on the date of the first restriction. The National Library dates the Immigration Restriction Ordinance to 1928, while other accounts place its effective application in 1930.⁸ The ordinance cut the number of Chinese immigrants from 242,000 in 1930 to 28,000 in 1933. It was followed by the Aliens Ordinance of 1933, which set quotas and charged landing fees for aliens.⁹

The end of unrestricted migration marked the end of the first globalisation in Singapore. For six decades the port had been open to ships, capital, information and people. The depression closed the gates for people and for much trade, while the coming war would close them for everything else.

The failure of the strategy

The Singapore strategy depended on the main fleet arriving in time. The planners first assumed a period of 42 days before relief. As tension rose in Europe, the period lengthened to 70 days in 1938, to 90 days in June 1939 and to 180 days in September 1939.¹⁰ With Britain at war in Europe, the fleet that the base was built to receive never came. A small force headed by the battleship Prince of Wales and the battlecruiser Repulse reached Singapore, only for both ships to be sunk by Japanese aircraft on 10 December 1941.¹¹

Japanese forces invaded Malaya on 8 December 1941, crossed the Johor Strait on 8 February 1942 and accepted the surrender of General Percival on 15 February. About 80,000 British, Indian, Australian and local troops became prisoners of war in Singapore, in addition to those captured in Malaya. Churchill called it “the worst disaster and largest capitulation in British history”.¹² Chapter I of Part C examines the occupation and its consequences for money and trust.

Notes

1. Wikipedia, “1915 Singapore Mutiny” (accessed November 2026): the mutiny of elements of the 5th Light Infantry began on 15 February 1915; “The mutineers killed 36 soldiers and civilians before the mutiny was suppressed by Allied forces”; landing parties from the French cruiser Montcalm, the Russian Orel and the Japanese cruisers Otowa and Tsushima from 17 February; Wikipedia, “1915 Singapore Mutiny” (accessed November 2026): more than 205 sepoys were court-martialled and 47 were publicly executed by firing squad at Outram Prison; 64 transported for life and 73 imprisoned for seven to 20 years. ↩
2. Wikipedia, “Anglo-Japanese Alliance” (accessed November 2026): signed on 30 January 1902; the Four-Power Treaty signed at the Washington Conference made the alliance defunct in December 1921; it “would not officially terminate until all parties ratified the treaty on 17 August 1923”. ↩
3. Wikipedia, “Singapore strategy” (accessed November 2026): Singapore was “chosen in 1919 as the location of this base”; the Washington Naval Treaty of 1922 set a 5:5:3 ratio for the British, US and Japanese navies and barred the fortification of Pacific islands, with Singapore as the exception. ↩
4. Wee Beng Geok, “The Story of Two Shipyards: Keppel & Sembawang”, BiblioAsia, vol. 15, issue 2, July–September 2019: Naval Base Scheme announced in 1923; 2,845 acres given in May 1923, valued at about £150,000 or 1.25 million Straits dollars; Hong Kong donated £250,000; the Federated Malay States gave £2 million in mid-1926; New Zealand committed £1 million in April 1927, “to be disbursed over eight years”; Wee Beng Geok, “The Story of Two Shipyards: Keppel & Sembawang”, BiblioAsia, vol. 15, issue 2, July–September 2019: contract awarded in 1928 to Sir John Jackson Ltd for £3.7 million; about 5,000 workmen and 100 British staff; 1.6 million tons of granite brought from Johor; floating dock with 50,000-ton lifting capacity commissioned in 1928. ↩
5. Wikipedia, “Singapore strategy” (accessed November 2026): the King George VI dry dock was formally opened on 14 February 1938 by Governor Sir Shenton Thomas; 42 vessels attended, including three US Navy cruisers. ↩
6. Wikipedia, “HMNB Singapore” (accessed November 2026): the King George VI Graving Dock, over 300 m long, was “the largest dry dock in the world at the time”; the base covered 21 square miles and was completed in 1938 at a cost of “£60 million”; Winston Churchill called it the “Gibraltar of the East”; Wikipedia, “History of Singapore” (accessed November 2026): the naval base was “Completed in 1939 at a staggering cost of $500 million”; compare Wikipedia, “HMNB Singapore”: completed in 1938 at a cost of £60 million. ↩
7. Wikipedia, “Kallang Airport” (accessed November 2026): opened on 12 June 1937 when Governor Sir Shenton Thomas “officially declared that Kallang Airport was now open to the public”; “the first purpose-built civil international airport to be established in Singapore”. ↩
8. National Library Board, Infopedia: the Immigration Restriction Ordinance was introduced in 1928, with improving Singapore’s sex ratio as one aim. ↩
9. Library of Congress Country Studies, Singapore, “Between the World Wars” (accessed November 2026): “Chinese immigration was drastically cut by the Immigration Restriction Ordinance of 1930”, put in force to combat unemployment resulting from the Great Depression; it “dropped the number of Chinese immigrants from 242,000 in 1930 to 28,000 in 1933”; “the Aliens Ordinance of 1933, which set quotas and charged landing fees for aliens”. ↩
10. Wikipedia, “Singapore strategy” (accessed November 2026): “The first estimate was 42 days”; increased in 1938 to 70 days with 14 more for provisioning; “further increased in June 1939 to 90 days plus 15 for provisioning and in September 1939, to 180 days”. ↩
11. Wikipedia, “Singapore strategy” (accessed November 2026): the strategy led to the despatch of Force Z; Prince of Wales and Repulse were sunk by Japanese aircraft on 10 December 1941. ↩
12. Wikipedia, “Fall of Singapore” (accessed November 2026): the Japanese 25th Army invaded Malaya on 8 December 1941; the first wave crossed the Johor Strait on 8 February 1942; Percival capitulated on the afternoon of 15 February; “About 80,000 British, Indian, Australian and local troops became prisoners of war”; Wikipedia, “Singapore strategy” (accessed November 2026): Churchill described the fall of Singapore as “the worst disaster and largest capitulation in British history”; nearly 139,000 troops were lost, about 130,000 of them captured in the campaign as a whole. ↩
13. Wikipedia, “Fall of Singapore” (accessed November 2026): “most of Singapore’s BL 15-inch Mk I naval guns could be traversed north and were used to engage the Japanese”; the guns were supplied mostly with armour-piercing shells intended for use against shipping. ↩

For general information only. This article does not constitute legal or tax advice, does not replace advice on an individual case and creates no lawyer-client relationship. It reflects the legal position as of October 2026.