The Liberal Imperialists were a faction within the British Liberal Party around 1900 regarding the policy toward the British Empire. They supported the Boer War which most Liberals opposed, and wanted the Empire ruled on a more benevolent basis. The most prominent members were R. B. Haldane, H. H. Asquith, Sir Edward Grey and Lord Rosebery.
The Liberal Imperialists believed that under the leadership of William Ewart Gladstone the Liberal Party had succumbed to "faddists", sectional interests, and the "Celtic fringe" which prevented it from being a truly national party. Furthermore, the Liberal Party should include people of all classes, along with promoting working-class MPs in the Liberal Party. They also argued that the Liberals had lost the centre vote because the party had distanced itself from "the new Imperial spirit". Instead, they argued for a "clean slate", that the Liberal Party must change if it is to succeed. The old, classical Liberalism must give way to the new ideas of "National Efficiency" and imperialism.
The grouping came to prominence shortly after the failed Jameson Raid in 1895 and prior to the outbreak of the Boer war four years later, as tensions between Britain’s South African colonies and its neighbours increased. Its leaders were members of the parliamentary Liberal Party – then in opposition – who supported the imperialist aspects of Lord Salisbury's Conservative government’s foreign policy. This stood in contrast to the radical wing of the parliamentary Liberal Party, whose prominent members included former leader William Harcourt, John Morley and David Lloyd George. Party leader Sir Henry Campbell-Bannerman, himself sceptical of Government foreign policy and particularly critical of the Colonial Secretary, Joseph Chamberlain, tried to bridge the gap between the two Liberal Party factions.
In the 1900 General Election Liberal Imperialist affiliated candidates were opposed by the Unionist Coalition. In particular, Joseph Chamberlain labelled the entire Liberal party as 'pro-Boer' and unpatriotic in the Second Boer War.
In 1902 the group changed its name to the Liberal League with more or less the same people involved. After the Liberal victory in 1906 they played major roles in the new Liberal government: Asquith, Grey and Haldane went to the Exchequer, the Foreign Office and the War Office respectively. 
- H. C. G. Matthew, The Liberal Imperialists. The Ideas and Politics of a Post-Gladstonian Élite (Oxford: Oxford University Press, 1973), p. viii.
- Matthew, p. 127.
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- Tyler, p 256.
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- H. C. G. Matthew, The Liberal Imperialists. The Ideas and Politics of a Post-Gladstonian Élite (Oxford: Oxford University Press, 1973).
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- Peter Stansky, Ambitions and Strategies (Oxford: Oxford University Press, 1964).
- Tyler, J. E. "Campbell-Bannerman and the Liberal Imperialists, (1906–1908)." History 23.91 (1938): 254-262. online</ref>