Aima, 19, is one of Britain's most prominent Black Lives Matter (BLM) activists, but at a protest in London, she is nervous. She has her hood up and, while a pandemic-mandated mask covers most of her face, she keeps her head down for fear of being recognized. Her eyes constantly dart to check the location of the police.

She has reason to be scared. Campaigners say that standing up for the rights of Black people in the UK comes at a high price. They say they've seen an angry backlash and have even received death threats.

Attending a march last month against a proposed bill to increase police powers at demonstrations, Aima was flanked by two white allies. Assigned by a trusted volunteer group, they are there to help keep her safe.

"If you are constantly getting people saying they want to kill you and they want you dead, then you don't feel safe anymore, you don't feel safe at all," she says.