Accountability sinks, accountability gaps and technological injustice: the case of the British Post Office/Horizon IT scandal

Purpose In complex systems, digitisation creates accountability sinks, whereby decision-making is delegated to computer systems so that humans are not responsible or in control. The accountability feedback loop is broken. Accountability sinks generate responsibility voids. These, in turn, lead to accountability gaps, creating technological injustice resulting in inequalities. This research develops a model of accountability for complex systems incorporating accountability sinks, responsibility voids and accountability gaps, highlighting the impact of digitisation that led to inequality for one group of workers. The British Post Office/Horizon Information Technology (IT) scandal has been described as the worst miscarriage of justice in UK legal history. Subpostmasters were imprisoned, fined and required to compensate the British Post Office for deficits in their branch accounts, caused by the malfunctioning of the Horizon IT branch accounting system. Design/methodology/approach This research operationalises Davies's (2024) concept of an accountability sink, developing an analytical framework for the purpose. The dataset is based on transcripts of 111 key witness statements at the public inquiry investigating the scandal. The authors apply their analytical framework to six elements relating to the Horizon IT system operating as an accountability sink. Findings Our analysis confirms that six elements of the British Post Office/Horizon IT outsourcing arrangement operated as an accountability sink. The case highlights the consequences of digitised systems for technological (in)justice. Originality/value The research operationalises the novel accountability sink concept and shows how such digital-system flaws, which are everywhere in modern society, contributed to inequality for one group of workers.