Abstract
The reliability of electricity supply has long been a central concern in the UK electricity supply industry. This study examines how conceptions of reliability evolved from nationalisation in 1948 through privatisation in the late 1980s and early 1990s, focusing on the renegotiation of reliability within a newly competitive market. Drawing on oral history interviews and archival sources, the study explores how privatisation reshaped system management, regulatory oversight, and the role of centralised control in maintaining reliability. The findings suggest that rather than a straightforward transition from state planning to market-driven efficiency, reliability was actively redefined to accommodate new industry structures while preserving essential system stability. This research contributes to historical and organisational studies by highlighting the contested nature of reliability in complex industries. It also offers insights for contemporary energy policy, particularly in balancing market mechanisms with the infrastructural and operational demands of electricity supply.