The Round Table Movement evolved out of Lord Milner's Kindergarten. They held meetings called 'The Moot', named after the Anglo-Saxon meeting, but also because they were discussing 'moot' points. The movement began at a conference at Plas Newydd, Lord Anglesey's estate in Wales, over the weekend of 4–6 September. The framework of the organisation was devised by Lionel Curtis, but the overall idea was due to Lord Milner. Former South Africa administrator Philip Kerr became secretary to the organisation.
In 1910 they would publish a journal The Round Table Journal: A Quarterly Review of the Politics of the British Empire. The aim of the original movement was closer union between Britain and the self-governing colonies, which Lionel Curtis believed could only be achieved by imperial federation, though others such as Leo Amery were in favour of improved co-operation.
In 1910–1911 Lionel Curtis took a tour of the Dominions to set up local Round Table groups. Groups were formed in Canada, the Union of South Africa, Australia, New Zealand, and a Newfoundland Group was set up in 1912.
Curtis composed a series of 'Round Table Studies' which were circulated to all the Round Table groups, and the comments were also circulated. Curtis hoped that he would be able to produce a collective volume arguing the case for imperial federation but agreement proved impossible, and in 1916 published The Problem of the Commonwealth under his name only.
In the course of his studies, Curtis developed the 'principle' of a Commonwealth as involving the progressive enlargement of self-government among its members, an idea which gained more favour among the Round Table groups than imperial federation. A sub-group including James Meston and William Marris considered the place of India in any scheme of federation, and concluded that India would have to be represented. During the First World War Philip Kerr developed the idea of a 'Commonwealth' further, as being antithetical to the German idea of 'empire'. Alfred Zimmern's brief entry in the movement during the War would bring it into disrepute amongst the British right.
The Round Table supported free trade despite Milner and Leo Amery's support for imperial preference, and endorsed the White Australia policy, publishing material by Frederic Eggleston on the matter.
With the entry of the United States into the First World War and the promotion of the League of Nations, the movement moderated its conception of the empire as a "Commonwealth of Nations" and concentrated on ways to improve communication and co-operation between Britain and the increasingly independent self-governing 'dominions'.
During the interwar period the Round Table groups continued to advocate a policy of collaboration among the Dominions of the British Empire (Canada and Newfoundland, Australia, New Zealand, Union of South Africa, and the Irish Free State) together with the United States. However, its embrace of the "Commonwealth" ethos also led it to support movements for self-government within the Empire such as the Anglo-Irish Treaty of 1921 and the Indian reforms of 1919 and 1935. In the late 1930s the contributors to the journal were split between those who advocated appeasement and those that did not.
The Round Table continued to exist for some time as a Commonwealth ginger group, designed to consider and influence Commonwealth policies, but since the 1980s has largely been a forum for discussion of Commonwealth matters.
Prominent members of the Round Table 'moot' in the first half of the twentieth century included
Prominent members of the Round Table 'moot' in the second half of the twentieth century included
Irish American academic Carroll Quigley believed that the Round Table Group was the front for a secret society for a global conspiracy of control set up by Cecil Rhodes named the Society of the Elect  to implement Rhodes's 'plan' to unite all English-speaking nations, and further believed that the elite of the British empire had an undue influence on the American elite. Sir Ivison Macadam thought Quigley was "crazy". As one writer noted, the "tragedy of Quigley was his conviction that he was outside of an inner circle that itself did not exist"