abolisment

In 1772 a runaway slave named James Somerset was the victim of an attempted abduction by Charles Stewart, his previous owner. While in London, Somerset had been baptized and his Godparents issued a writ of habeas corpus (a legal action through which a person can seek relief from unlawful detention of himself). Chief Justice of the King’s Bench, Lord Mansfield, had to judge whether the abduction was not under English Common Law as there was no legislation for slavery in England. It was thus declared that the condition of slavery did not exist under English law. This judgement by Lord Mansfield emancipated the thousands of slaves in England.

http://en.wikipedia.org/wiki/Ablitionism#first_steps