British idealism was a movement of political philosophy that was influential during the mid to late nineteenth century and the early days of the twentieth century. Leading figures were T.H. Green (1836-1882), F.H. Bradley (1846-1924) and Bernard Bosanquet (1848-1923).

Though much more variegated than some commentaries would seem to suggest, British idealism was generally marked by several broad tendencies: a belief in an Absolute (a single all-encompassing reality that in some sense formed a coherent and all-inclusive system); the assignment of a high place to reason as both the faculty by which the Absolute's structure is grasped and as that structure itself; and a fundamental unwillingness to accept a dichotomy between thought and object, reality consisting of thought-and-object together in a strongly coherent unity.

In some sense this movement was a favorable reaction to the German Idealist movement -- particularly such philosophers as Immanuel Kant and G.W.F. Hegel, who were characterised by Green, among others, as the salvation of British philosophy after the alleged demise of empiricism. The movement was certainly a reaction against the thinking of John Locke, David Hume, John Stuart Mill, and the utilitarians. Some of those involved would have denied any specific influence, particularly in respect of Hegel. Nevertheless, James Hutchinson Stirling 's book The Secret of Hegel is believed to have won significant converts in Britain.

Certainly British idealism was influenced by Hegel at least in broad outline, and undeniably adopted some of his terminology and doctrines. Examples include not only the aforementioned Absolute, but also a doctrine of internal relations , a coherence theory of truth, and a concept of a concrete universal. Some commentators have also pointed to a sort of dialectical structure in e.g. some of the writings of Bradley. But none of the British idealists adopted Hegel's philosophy wholesale, and his most significant writings on logic seem to have found no purchase whatsoever in their thought (nor in British thought generally).

On its political side, the British idealists were largely concerned to refute what they regarded as a brittle and "atomistic" form of individualism, as espoused by e.g. Herbert Spencer. In their view, humans are fundamentally social beings in a manner and to a degree not adequately recognized by Spencer and his followers. The British idealists did not, however, reify the State in the manner that Hegel apparently did; Green in particular spoke of the individual as the sole locus of value and contended that the State's existence was justified only insofar as it contributed to the realization of value in the lives of individual persons.

The hold of British idealism in the UK weakened when Bertrand Russell and G.E. Moore turned against it, and their education in the tradition. At that point British philosophy in general revolted once more against metaphysics in general. The later work of R.G. Collingwood was a turning back, if relatively isolated. Among present-day UK philosophers the best-known exponent of absolute idealism is probably Timothy L.S. Sprigge.

British idealism's influence in the United States was somewhat limited. The early thought of Josiah Royce had something of a neo-Hegelian cast, as did that of a handful of his less famous contemporaries. American rationalist Brand Blanshard was so strongly influenced by Bradley, Bosanquet, and Green (and other British philosophers) that he could almost be classified as a British philosopher himself. Even this limited influence, though, did not last out the twentieth century.