Peter Francis is the ex-Metropolitan police officer turned whistle-blower who revealed how he spied on the family of Stephen Lawrence in their fight for justice. His evidence was significant in leading to the current public inquiry. Whistle-blowers are crucial; they provide inside knowledge and understanding, and are uniquely placed to draw public attention to institutional wrongdoing.

Becoming a whistle-blower is not easy. You can become isolated from colleagues. You might be regarded as a traitor. You’ll run the risk of being smeared, discredited and – depending on what you disclose – prosecuted under the Official Secrets Act.

Why would you take that risk?