Following on from a call in 2016 by UN Special Rapporteur Juan E. Mendez for a ‘universal protocol’ on standards for non-coercive interviewing methods, new Principles for Effective Interviewing have now been published; investigative interviewing specialist Professor Ray Bull, a member of the committee which drew up the new principles, explains the reasoning behind them, the standards they set, and the likely impact on good practice in policing.