The Effects of Delayed Abolition in the British Empire?

hey, all. recently i made a thread about if Britain was less-affected by the Black Death than the rest of Europe, and one supposition that came up as a result was that Britain retains serfdom for a while longer than IOTL. i'd like to look a little more into that in this thread and see what everyone thinks would happen if the abolition of slavery/serfdom in the British empire was delayed by any of three different spans of time (for quick reference, the Abolition of the Slave Trade Act was passed in 1807):

  • ~15 year delay: the Abolition Act is passed around 1822--significant events which took place between 1807 and 1822 included the Napoleonic Wars, wars of independence in Latin America and the Balkans, the War of 1812, the Russo-Persian War, the Third Anglo-Maratha War, George IV ascended, steam boats became more advanced, and Louisiana, Indiana, Mississippi, Illinois, Alabama, Maine, and Missouri were ratified as US states
  • ~25 year delay: the Abolition Act is passed around 1832--significant events which took place between 1807 and 1832 included (along with those above) William IV ascending, several wars begin between teh US and Amerindians, and the lead-in events to the Texas Revolution
  • ~35 year delay: the Abolition Act is passed around 1842--significant events which took place between 1807 and 1842 included (along with those above) the first Opium War and the Treaty of Waitangi
what i'm mainly interested in determining is what the effects of later British abolition would be on other countries in the world (particularly the US and possibilities concerning the ACW) and on British society in general. Britain was pretty much the first European country to abolish slavery in the broader modern period, so without them to give an example at the same time as IOTL, would other countries abolish sooner or later, for instance?
 
There is a difference between slavery (a slave is a chattle, a thing) and a serf (a peasant tied to the land) - at least in the eyes of the law, if not in how it feels.

The British banned the Slave Trade in 1807, they didn't ban slavery until 1997!

That said if the 1807 Act didn't pass then the Radicals in Parliment and the Bloomsbery Sect would have ramped up their campaign.

Since the Navy had head money for capturing slave ships it was a useful revenue stream for them after the Napoleonic War.
 
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