In 1833 the British borrowed 40% of their national budget to buy freedom for all slaves in the British empire. The debt was only repaid in 2015. https://www.usatoday.com/story/news/factcheck/2020/06/30/fact-check-u-k-paid-off-debts-slave-owning-families-2015/3283908001/

In 1833 the British borrowed the equivalent of $17B (40% of national budget) to buy freedom for all slaves in the British empire. The debt was only repaid in 2015.

https://www.usatoday.com/story/news/factcheck/2020/06/30/fact-check-u-k-paid-off-debts-slave-owning-families-2015/3283908001/