An independent review found no evidence that Britain’s grid operator instructed staff to suppress records during June’s heatwave, while a separate regulator inquiry continues to examine workplace culture and operations.
Law firm Eversheds Sutherland (International) LLP investigated Britain’s National Energy System Operator (NESO), interviewing 36 witnesses across the organization. Its report, published Oct. 19, found no evidence staff had been told to delete, alter or suppress records, or that Corporate Affairs personnel directly interfered with control room decisions.
Conservative MP Claire Coutinho told Parliament in July that whistleblowers had contacted her with concerns about grid security, record keeping and possible Corporate Affairs involvement in operational decisions. Eversheds examined those allegations; its remit did not include deciding whether the electricity system met security standards.
The report also flagged cultural and governance concerns. Some witnesses said senior leaders lacked a clear understanding of control room work and the pressures on staff as demands on electricity networks grew during Britain’s shift toward net-zero emissions. Eversheds recommended changes to workplace practices and controls, including how employees raise concerns and how NESO responds. NESO said it accepted the recommendations and its board would oversee an implementation plan.
The Office of Gas and Electricity Markets (Ofgem), which is conducting a separate inquiry, said electricity supply to consumers was maintained during the June 22-26 heatwave. On June 23, frequency stayed below NESO’s normal lower bound of 49.8 Hz for extended periods that evening, although it remained within statutory limits during the week. Ofgem has not determined whether the system remained secure or all required procedures were followed. It is also examining whether workplace culture or concern about reputational sensitivity affected decisions and procedures.
Ofgem identified extreme heat, higher demand, reduced generation availability and changing interconnector flows as factors contributing to grid strain. It has not apportioned their effects or established a cost to consumers.
NESO’s review team is due to submit its final report to Ofgem by Dec. 11. The regulator aims to publish its conclusions on grid security by Jan. 31, 2027.
