We all know Britain has a glorious past: the Empire, the innovation, the invention, the wonderful art, culture, and language, but some intellectuals from that country also share stories of the shame they have knowing the atrocities their country did in the past, slavery is one of the most debated, there's a feeling of shame particularly among young people which is an interesting phenomenon for sociologists.
Some point out the fact that the movement to abolish slavery started in the 1780s. Looking at the history we would see that the slave trade within Britain and it's colonies was abolished in 1807 although only effectively enforced from 1811. From that date until 1860 the Royal Navy was used to suppress slave trading between West Africa and the Carribean by any countries. The 1807 Act did not however abolish slave owning. The fight to do that continued and in the 1830s the Govt realised that the only way that they would be able to do that was to buy off the owners who had strong representation in Parliament. That resulted in the 1833 Slavery Abolition Act.
Some historians acknowledge that the British were the first civilisation in all of human history to abolish the slave trade and forced others to do so as well with the power of the British Navy.
Others defending the British also mention the British were also an occupied nation by the Romans, the Vikings, the Goths, the Saxons, the Normans, all who invaded Britain and enslaved its people.
Certainly the British were not the only ones conquering others but the inmense influence the English language and culture has in the world makes it more likely to be in the spot light.