Dr Martin Luther King was once asked why African Americans had found it difficult to integrate into United States society, and to prosper as other immigrant groups had prospered. He explained that the crucial distinction was that the original black population of America had arrived unwillingly in chains, whereas the others had come of their own free choice. It was an intriguing reply, for it implied that the method of migration from one country to another has a decisive influence on the fate of the migrants’ descendants for many generations after the actual event.

The demolition of the statue in Bristol of Edward Colston and its subsequent undignified tipping into the river has a direct relevance to the Black Lives Matter demonstrations across the US and elsewhere. They began as a protest against the killing of George Floyd by a Minneapolis police officer, and drew their strength from the widespread knowledge that this case was far from unique. Something is wrong with American policing, not just its methods but its culture, and the incidents of unlawful killings of black people in police custody are only the most extreme manifestation of a deeply flawed system.