Thai Legal Studies (2026) Vol. 6 No. 1 | 43–48
https://doi.org/10.54157/tls.289980
© 2026 by Papawadee Tanodomdej

This is an open access article, distributed under the terms of the Creative Commons Attribution License (CC BY 4.0, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

Book Review

The Anglo–Siamese Negotiations, 1900–1909

Thamsook Numnonda
International Studies Center, Ministry of Foreign Affairs (2025)
336 pp., ISBN 978-616-341-177-8

Papawadee Tanodomdej*

Keywords: Siam — Extraterritoriality — Semi-colonialism — Territorial sovereignty — Quid pro quo

Thamsook Numnonda’s The Anglo–Siamese Negotiations, 1900–1909, published in 2025—and thus six decades after it was submitted as a doctoral thesis to the School of Oriental and African Studies (SOAS) in 1966—fits surprisingly well into current critiques of Siamese/Thai historiography. While her thesis included limited theoretical claims or analysis of how Anglo–Siamese negotiations reflected the broader picture of late 19^th and early 20^th-century imperialism, this book review argues that the study was nonetheless well ahead of its time. To be sure, Thongchai Winichakul’s Siam Mapped: A History of the Geo-Body of a Nation (first published in 1995) eventually sparked a debate about whether Siam had remained truly independent amidst surrounding colonial threats—or whether it merely maintained nominal independence while, in fact, it was considered a semi-sovereign polity by European imperialists.¹ But Thamsook’s work, submitted almost three decades earlier, was already groundbreaking in its own right.

Anglo–Siamese Negotiations is at once a period piece, shaped by the history of Anglo–Siamese negotiations on a series of treaties between 1900 and 1909, and a still-useful documentary excavation of the decade in which Siam's jurisdictional independence was purchased through a systematic renegotiation of what sovereignty itself was permitted to mean. The book’s belated appearance in 2025 coincides with current scholarly interest in the sovereignty transformation of semi-sovereign polities through their encounters with 19^th and early 20^th-century imperial powers, from renewed debates over the legacies of unequal treaties in Asia and elsewhere to broader reassessments of how “informal empire” reshaped the legal architecture of non-European polities without formal annexation.² Through its chronicle of Foreign Office dispatches and Siamese Court correspondence, the book also illustrates the diffusion of the European idea of sovereignty—with a defined territorial sovereignty and a “standard of civilization”—to non-European polities in the imperial context.

Professor Emerita Thamsook’s framework is conventional bilateral diplomatic history. Five chapters track inherited problems of extraterritoriality, the 1897 Secret Convention between Siam and Britain, the railway question during Siamese modernization, and the disputed sovereignty (suzerainty) over the Northern Malay States against the backdrop of Anglo–Siamese negotiations over the Siamese–Kelantan Agreement of 1902, the abrogation of the 1897 Secret Convention through the conclusion of the Anglo–Siamese Treaty of 1909, and the influence of the Franco–Siamese Treaty of 1907 over the conclusion of the Anglo-Siamese Treaty of 1909. Its organizational logic is chronological and instrumental rather than analytical, since each chapter narrates a negotiation until its conclusion before moving to the next, with minimal cross-referencing of the deeper structural continuities that linked them. The reader is left to theorize against dense and largely unmediated documentary records drawn from the British Foreign Office, the Colonial Office, and Thailand’s National Archives. However, these documentary records tell a remarkably coherent story about Siam’s semi-colonial condition even if Thamsook did not directly name it as such.

Chapter I establishes the imperial context prevailing at the Siamese Court before 1900. The opening sentence, “I am most certain that as long as I breathe, I will not see Siam without her independence,” was a quote from King Chulalongkorn’s correspondence with Krom Luang Pichitprichakorn, lamenting Siamese struggles over its nominal independence after the Paknam incident when a French warship crossed the bar to the Chaopraya river without Siamese consent, eventually resulting in the Siamese relinquishment of its territorial claim over the left bank of the Mekong river. The quote reflects Thamsook’s purpose in writing her PhD thesis (now a book) to tell the story of the Siamese struggle with two competing imperial powers, Britain and France, focusing on Siam’s ability to release itself from a semi-colonial condition into equality. The problem of extraterritoriality is therefore mentioned to guide the reader through the preceding context, i.e., before the 1900–1909 Anglo–Siamese negotiations (pp. 14–31). The extension of the extraterritoriality clause of the 1855 Bowring Treaty to British Asian subjects caused the Siamese Court’s frustration as Siam was attempting to demonstrate its equal status and thus to limit the application of British law and consular courts to actual Britons residing in Bangkok.

In the first chapter, Thamsook also raises the interesting question of how Siam viewed the political “influence” of the two competing colonial powers (Britain and France) (p. 13). She opines that the influence from the British and the French over Siam’s internal and external affairs could be attributed to different reasons. Siam admired and trusted the British government, education and long-term commercial and political relations, while, in contrast, the French influence was due to the Siamese fear of French aggression. This thought-provoking stance may also shed light on the broader question why English law has left a significant imprint on the Thai legal system, which has so far not been addressed by the current scholarly works on legal transplantation.³ Reading this first chapter against the literature on the standard of civilization⁴ and crypto-colonialism⁵ may provide new perspectives on the Siamese craving for civilization and its adoption of the British system as a model to achieve such civilized status.

Chapter II contextualizes the inconveniences of the 1879 Secret Convention as they were experienced by both the Siamese and the British. The British sphere of influence, laid out in Article III of the Convention, complicated Siam’s exercise of sovereign powers in the Southern tributaries, including Kelantan. Although Thamsook does not engage directly with the question of sovereignty between Siam and its tributaries, it may be noted that, when the Convention was concluded, the relationship between Siam and Kelantan was still based on the Mandala system, which did not implicate Siamese sovereign power to authorize mineral concessions on behalf of its tributaries. The “Duff affair” of 1900, when R. W. Duff, a retired British officer in the Straits Settlements, prematurely sought a mineral and trading concession directly from the Sultan of Kelantan rather than through the Siamese government in Bangkok, showcases these Siamese and British quandaries. While Duff pressured the British Foreign Office to endorse his mineral concession in Kelantan, the British Minister in Bangkok was instructed to refuse the request due to the British acknowledgement of Siam’s sovereignty over Kelantan (p. 65). The Duff affair also foregrounds British interference in Kelantan and Trengganu through its pressure on Siam to appoint British nationals as Siamese representatives in Kelantan to strip the Sultan from authority over the concession. The Sultan of Kelantan’s pledge for British protection, after the Duff affair, served British colonial aspirations of turning Siamese Southern tributaries into British Malaya (p. 77). Thamsook discloses the correspondence exchanged between Siam and the British Foreign Office over the status of Kelantan and Trengganu, which include references to Siam’s position of “sovereignty” over these two tributaries and to the British term “dependencies.” The legal terms illustrate the Anglo–Siamese wrestling over sovereignty in the Southern tributaries.

Chapter III on the Malay Peninsula Railway and the Franco–Siamese Treaty of 1907 covers two separate negotiations—one with Britain and one with France. Thamsook shows how these two issues supplied both a template and a stimulus for the later Anglo–Siamese negotiations. The first half of the chapter traces the Malay Peninsula Railway negotiations of 1906–1907. Siam’s modernization project to construct its railway network southward into the Southern tributaries was complicated by the fact that the Siamese Royal Railway Department was dominated by German engineers (even if they were Siamese officials). The chapter depicts the British anxiety that its imperial interests on the Malay Peninsula would be compromised if Germans were allowed to obtain a footing in the area (p. 117). The British, therefore, invoked the spirit of the 1897 Secret Convention, calling on Siam to outright dismiss the German railway project.

The second half of the chapter turns to French imperialism as expressed through the Franco–Siamese Treaty of March 23, 1907. Thamsook traces nearly two decades of Franco–Siamese friction, including the Paknam incident (p. 131). The French extensive interpretation of the extraterritorial clause in Article IV of the 1893 Franco–Siamese Convention to cover any subjects of countries which had no treaty with Siam triggered the kingdom’s distress over the French colonial threat and the attempt to deprive it of judicial independence. Seeking assistance from the British as well as from the American advisor Edward Henry Strobel, Siam was able to negotiate the Franco–Siamese Treaty, exchanging Battambang, Siemreap, and Sisophon—provinces of Siamese tributaries—for the return of Krat and the Donsai islands, and, critically, for France’s agreement to submit its Asian protégés to the international court system with the participation of Siamese judges. Thamsook considers that Siam gained considerable political advantage through the conclusion of the Franco–Siamese Treaty of 1907 that ended the French abuse of extraterritorial rights over Asian protégés by surrendering its territorial claims (pp. 138–140). Her account of the Franco–Siamese 1907 negotiations illustrate a point that was later made by Martti Koskenniemi who argued that no stable standard of civilization existed to decide how an uncivilized or semi-civilized polity could become a civilized nation.⁶ Rather, ending the French extension of extraterritoriality to Asian protégés succeeded through a quid pro quo that bartered French colonial ambitions in Eastern areas under Siamese control against Siam’s gradual release from the semi-civilized community.

Chapter IV tells the history of the final phase of Anglo–Siamese negotiations, 1907–1909, depicting the Siamese cession of Kelantan, Trengganu, and Kedah to Britain in exchange for both the British abandonment of extraterritoriality and a financial arrangement to complete the railway project southward into the area left under Siamese territorial sovereignty. This chapter continues the discussion on how Siam’s core foreign policy of quid pro quo was employed in its relations with Britain to pave the way for the Siamese modern-nation kingdom.

Chapter V covers the aftermath of the conclusion of the Anglo–Siamese Treaty of 1909, including the transfer of Kelantan, Trengganu, and Kedah. The Treaty required the settlement of the political status of these former Siamese tributary Sultanates (pp. 193–195). Thamsook clearly points out that the status of these former tributaries differed from the Federated Malay States under British colonial governance. An abrupt deprivation of the Sultans’ authority would have led to an uprising against British residents. Britain, therefore, decided that the British officers in these former tributaries would be styled as “Advisors” rather than “Residents.” This allowed the Sultans to nominally maintain a position of authority but require asking and acting upon British advice in all matters other than those involving the Mohammedan religion and Malay customs. These documentary records are important for research on the implications of different types of colonial rule imposed upon Malay states. The concluding chapter thus sheds a strong light on how the conversation between the imperial powers and semi-colonial Siam on sovereignty and its ancillary aspect of jurisdiction were construed. It fits into the broader picture where ideas of sovereignty could be deemed as a commodity, trading off territorial claims for judicial independence, with the hope to join the civilized.

In sum, the publication of this book by the International Studies Center (ISC), 60 years after it was submitted as a doctoral thesis to SOAS, is a treasure trove for prospective research on semi-colonial Siam and the European powers as well as on legal transplantation. Some of the correspondence exchanged between Siam and European powers reflect an enthusiast diffusion of European legal ideas to non-European polities, including British subjects’ right to hold land in Siam, which was transformed, as the author provided a detailed conversation, after the conclusion of the Anglo–Siamese Treaty of 1909.

In addition to the book’s value for prospective research, Professor Emerita Thamsook’s life-long contribution to scholarship on critical Thai history is equally worth mentioning. Her later book, “Thai Politics During the Second World War” (first published in 1978), contains most critical research that links state-led discourse on nationalism to General Pibulsongkram’s race for civilization during the Second World War.⁷ The decision of the General to join the Axis with the Japanese Empire, while adopting the Western-styled cultural mandates (Rattha Niyom) such as mandatory hat-wearing in public spaces and the suppression of the traditional Thai cultures such as Betel nut chewing, demonstrates the contrasting image of nationalism-building happening elsewhere in the same period. Another of her works, “The Historical Facts on the First Generation of Siamese Young Turk Rebels During 1912 (RorSor 130)” is a foundational history of Siamese Young Turk rebels.⁸ The book showcases how the actual causes of the Siamese Revolution resulted from centralization during the reign of King Chulalongkorn. Thamsook was the daughter of one of the 1912 first-generation Young Turks.⁹ Her critical stance is therefore perhaps not surprising, also when compared to the work of some of her peers such as, for instance, Professor Pensri Duke.¹⁰

While Professor Emerita Thamsook passed away in 2022, her precious work, including this book, carries her legacy forward for generations to come.

Suggested Bibliographic Citation:¹¹

Papawadee Tanodomdej. Review of The Anglo-Siamese Negotiations, 1900–1909,
by Thamsook Numnonda. (2026) 6(1) Thai Legal Studies 43–48.
https://doi.org/10.54157/289980