This British policy was clearly announced to the world in the negotiations at Vienna in 1814-15.

But Britain herself still supported the institution of slavery in her West Indian colonies and it was not until British humanitarian sentiment had forced emancipation upon the unwilling sugar planters, in 1833, that the nation was morally free to criticize American domestic slavery.

Meanwhile great emancipation societies, with many branches, all virile and active, had grown up in England and in Scotland.

These now turned to an attack on slavery the world over, and especially on American slavery.

The great American abolitionist, Garrison, found more support in England than in his own country; his weekly paper, _The Liberator_, is full of messages of cheer from British friends and societies, and of quotations from a sympathetic, though generally provincial, British press.
From 1830 to 1850 British anti-slavery sentiment was at its height.