The United Kingdom’s competition regulator has launched its first-ever advertising campaign to entice “insiders” to blow the whistle on cartels for cash and for companies to gain immunity from prosecution if they inform on their co-conspirators first.

The Competition and Markets Authority’s (CMA) campaign, called “Cracking down on Cartels,” wants to make more people aware that they can potentially earn a reward of up to £100,000 if they report on any illegal activity they witness that results in a prosecution. Informants will also be promised anonymity.

Neil Hodge is a freelance business journalist and photographer based in Nottingham, United Kingdom. He writes on insurance and risk management, corporate governance, internal audit, compliance, and legal...