“Formation” is a cinematic video and, to a British viewer, its location in the Deep South of New Orleans and stylised foregrounding of African American black identity is at a cultural remove. So, too, is a lot of its political context. America, we learn, is in a new civil rights struggle. Filtered via transatlantic news coverage, the flaming cars of Ferguson and ranks of armed police in response to rioting can feel almost unreal to us Brits. American racial politics can seem extreme, polarised and violent. Our police, here in Britain, do not routinely carry guns. We – and by this, I particularly mean white British people – can be sure we have none of these issues. For us, “Formation”, much like the twists and turns of the US presidential election, is pure spectacle – a fascinating commentary on divisive politics in another world. #BlackLivesMatter seems a fair enough sentiment in that context – no wonder African Americans are angry!

In between all the Beyoncé tweets and article shares on social media, however, I also saw a Facebook event organising a vigil in London last Monday, following the funeral of Sarah Reed. Reed was a young black woman who, four years ago, was assaulted so brutally by an arresting officer, he was convicted and suspended. Having been the victim of state violence once, Reed became was arrested in hospital while receiving mental health treatment and taken to Holloway Prison. In January, she was found dead in her cell – her family were told she had “strangled herself” while lying down on her own bed. To many, this seems improbable. Reed’s story is a tragic and alarming one – that a black woman with mental health issues seems to have been failed by the police once only to be failed fatally by the prison service has rightly provoked anger and a drive to organise by Black Minority & Ethnic (BME) activists in Britain.

An investigation by the Institute of Race Relations last year found that 509 BME people had died in state custody in the past 24 years, and no officer has been convicted in any of these cases. Reed now joins these horrifying statistics. Many individual stories among these numbers are shocking – such as that of Joy Gardner, who police restrained with leather straps and gagged with adhesive tape wrapped around her head, asphyxiating her in 1993; or Olaseni Lewis, suffocated on a hospital floor by 11 police officers while a patient in mental health services in 2010. Both families continue to seek justice for the deaths.