The scope of claims against the police has broadened in recent years. For example, the Supreme Court recently held that the state has an obligation to carry out an effective investigation when it receives a credible allegation of serious harm, in the John Worboys (black cab rapist) case. What happens when police officers struggling with a suspect injure a passer-by? Or where a woman is murdered after she makes a 999 call? Writing in NLJ this week, Dijen Basu QC, of Serjeants’ Inn Chambers, discusses this fast-evolving area of law.