Back in england they had ruled in 1772 that English law did not recognize slavery, so the threat to the american slave owners was very real.
Not really. Slavery had never been well-established in England, and the British were still massively invested in slavery in all of their colonies and showed no appetite for stopping. There was no immediate risk of abolition and very little of the writing from Southerners in the American Revolution is concerned with the prospect of abolitionism from the British Empire. When the Brits took Martinique from the French Republic, which had at that time abolished slavery, they went out of their way to ensure that slaves did not receive this promised abolition, neither from the Republic nor in service against French forces.
For that matter, abolitionism in the South itself was on the rise, until the 1790s and the invention of the cotton gin, which gave slavery an order of magnitude extra economic incentive.
Not really. Slavery had never been well-established in England, and the British were still massively invested in slavery in all of their colonies and showed no appetite for stopping. There was no immediate risk of abolition and very little of the writing from Southerners in the American Revolution is concerned with the prospect of abolitionism from the British Empire. When the Brits took Martinique from the French Republic, which had at that time abolished slavery, they went out of their way to ensure that slaves did not receive this promised abolition, neither from the Republic nor in service against French forces.
For that matter, abolitionism in the South itself was on the rise, until the 1790s and the invention of the cotton gin, which gave slavery an order of magnitude extra economic incentive.