Sir Lenny Henry has written an open letter urging black Britons to take the Covid-19 vaccine. The comedian and actor said people should "trust the facts" and guard against misinformation. The letter has been signed by high-profile figures such as actor Chiwetel Ejiofor, YouTube star KSI and actress Thandie Newton. Vaccination rates among black Britons are considerably lower than among white Britons. What more needs to be done to encourage black Britons to take the vaccine? What is the problem here and how can we resolve it?