Which British monarch has their hands dirty with the blood of millions? The obvious cases where British policy led to that many deaths would be e.g. the Irish a

Which British monarch has their hands dirty with the blood of millions? The obvious cases where British policy led to that many deaths would be e.g. the Irish and Bengal famines (the latter during WWII). Those both took place at a time when the monarch was a constitutional figurehead. The best case might be the slave trade. But this was at its height under the Hanoverians, by which time the Commons was already the effective supreme power. I suppose you could say that the slave trade started earlier, and that this starting event caused the later expansion. Maybe, but that's a claim about the causal chain that needs arguing for.