The UK's public spending watchdog, the National Audit Office (NAO), has issued a stark warning about the expansion of electronic tagging in England and Wales, highlighting significant risks to public safety. This comes as the government aims to combat prison capacity issues by managing more offenders in the community. The NAO's report underscores the need for robust improvements to the system, which is already under strain, before further expansion can be considered safe or effective.
The number of people being electronically monitored has doubled to 28,700 over five years, with projections indicating a continued rise. However, the report raises serious concerns about the effectiveness of the system, suggesting that thousands of individuals may not be actively monitored. As of March 2026, the HMPPS was reviewing approximately 8,900 cases, with the MoJ suggesting a lower figure of around 5,450 unmonitored cases. This discrepancy highlights the need for transparency and accountability in the system.
One of the key issues identified is the poor performance of an external contractor, Serco, which was responsible for tagging individuals on time and notifying officials of potential breaches. Between August 2024 and July 2025, Serco failed to meet its timeliness targets, leading to a significant backlog of visits to fit, check, or remove tags. This backlog peaked at 7,000 in October 2024 before decreasing to fewer than 400 in November 2024. The report also notes delays in fitting individuals with tags, with Serco only successfully fitting tags on 62% of the people it visited within its two attempts in February 2026.
The NAO's concerns extend to the estimated shortfall of about 2,200 probation staff as of March 2026, which further undermines the system's ability to scale up safely. The report emphasizes that the expansion of the electronic monitoring system will not be efficient or effective unless the MoJ and HMPPS address critical weaknesses in governance, data quality, and system-wide inefficiencies. These weaknesses include a lack of clear contingency plans, poor performance from external contractors, and a lack of transparency in monitoring and breach response.
Gareth Davies, the head of the NAO, underscores the urgency of the situation, stating that electronic monitoring is central to managing prison pressures but is not currently working effectively, creating risks to public protection. Sir Geoffrey Clifton-Brown, the chair of the public accounts committee, echoes these concerns, highlighting the government's lack of knowledge about the number of unmonitored individuals and its inability to respond quickly to breaches, which poses unknown risks to public safety.
Pia Sinha, the chief executive of the Prison Reform Trust, shares these concerns, warning that expanding the use of tagging without addressing wider pressures could undermine public confidence and safety. She emphasizes the need for investment in probation, robust safeguards, and a clear understanding of what success looks like to ensure that electronic monitoring is an effective tool for reducing reoffending and rebuilding lives.
The government has allocated up to £175 million to fund the expansion over the years of 2026-2029, with a focus on public protection. However, the NAO's report and the concerns raised by various stakeholders suggest that significant improvements are necessary before the expansion can be justified. The MoJ's spokesperson acknowledges the challenges, citing a failing tagging system with record backlogs and highlighting recent improvements in install rates and investment in the probation system.
Despite these efforts, the NAO's warning serves as a stark reminder that the expansion of electronic tagging must be accompanied by robust improvements to governance, data quality, and system-wide inefficiencies to ensure public safety and the effective management of offenders in the community.
