The legal arguments that would support a principled refusal of reparations are well known to the British government. Its lawyers have undoubtedly prepared detailed advice on them. The decision not to make these arguments publicly is a political decision, not a legal uncertainty.
Ministers have presumably been advised that making the legal arguments would generate accusations of defending slavery, would be politically damaging, and would energise the reparations campaign rather than dampening it. These concerns are understandable. They are also a form of political cowardice that sacrifices honest debate for short-term risk management.
The legal arguments are correct. Making them publicly would be the honest thing to do. The fact that the government consistently fails to do so is a failure of political leadership that serves neither Britain’s interests nor those of Caribbean communities who deserve honest engagement rather than managed prevarication.