If anyone is curious:

The Slavery Abolition Act 1833 (3 & 4 Will. 4. c. 73) was an act of the Parliament of the United Kingdom which abolished slavery in the British Empire by way of compensated emancipation.

But…

Slavery had been judged to be without legal basis in England in 1772. In May of that year, Lord Mansfield’s judgment in the Somerset case emancipated a slave who had been brought to England from Boston in the Province of Massachusetts Bay, and thus helped launch the movement to abolish slavery throughout the British Empire.

So yeah, the ruling was in 1772 and the US decided to declare their independence and the Preamble begins with:

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

* Except for slaves…

All of this is from Wikipedia.