What does the UK, France and the Netherlands have in common?

[Sarmatian]

Such a payment would come from taxes, nobody alive today who pays taxes is responsible for slavery, ergo this is stupid.

Nobody alive today who pays taxes was responsible for ww2, yet current German taxpayers still pay for it.

Countries are entities in foreign policy and international law. Just because there's a new generation doesn't mean international treaties and international law doesn't apply.

Stupid though the claim is, I still wouldn't mind the claimants paying us for the cost of maintaining the Royal Navy for a century, scaled to 2013 levels.

First you'd have to prove that the sole purpose of the Royal Navy for a century was to enforce abolition of slavery.