The slave trade was a prosperous industry throughout the 1800s and fell into decline in the 1900s, it was banned universally in 1940 by Prime Minister Winston Churchill.
The slave trade included people from African, Chinese, and Indo-Asian ethnicity and faced many movements to ban it. The slave trade was briefly banned in the United Kingdom until the Confederacy re-instated it in the Confederate Kingdom. The USA was also free from slaves and they attempted to relinquish them in the War of Northern Aggression. Many historians believe that had the USA won, the slave trade could have been banned 70 years previously.
When the Confederate Kingdom was created Queen Victoria requested that those from India could be protected from the Slave Trade, this was agreed and in return she promised not to intervene in other regions.
While laws allowed people to keep their property 'slaves'. The British Government agreed with slave traders that in order to upkeep the trade, the children of slaves should be granted freedom. The British Government also placed acts to prevent the mistreatment of slaves and as of 1892, whipping was banned.
In 1894 the British Government issued the 'Free Subjects Act', this banned any future transactions of slavery in regions of the British Empire, this was agreed with the Confederacy, so long as current slaves would remain under their masters control.
In 1920 all current slaves were deemed property of the crown and they were therefore set free, the CK agreed to compensate all owners. The British were popular throughout the empire and people enjoyed the freedoms which came with it.
In 1929, several new colonies were granted freedom from slavery, including Egypt.
In 1940 Churchill met with CS President Roosevelt and together they agreed to end the slave trade, all slaves were set free and several traders were imprisoned.