A significant number of criminals ordered to wear electronic monitoring devices are not being fitted with tags, according to a new report from the National Audit Office (NAO). The findings raise concerns about the effectiveness of the Ministry of Justice's (MoJ) electronic tagging program and its ability to safely scale up to manage increasing numbers of offenders in the community.
At the end of March, nearly 9,000 individuals, amounting to a quarter of those subject to tagging orders either by court or upon release from prison, had not been fitted with electronic tags. Updated figures from the MoJ indicate this number was closer to 5,450, or one in seven of the 37,600 individuals under tagging orders at that time. The NAO report states that the HM Prisons and Probation Service (HMPPS) lacks an accurate understanding of how many offenders should be tagged but are not, highlighting a significant number of unmonitored individuals.
Auditors found that MoJ officials cannot reliably determine if untagged criminals commit new offenses or the duration for which they remain unmonitored. The report identified "significant unmonitored time periods of high-risk offenders." This situation is exacerbated by other system inefficiencies. The contract with tagging operator Serco reportedly allows up to 53 hours to report an offender's breach to probation teams or police. Staff are also reportedly overwhelmed by 530,000 to three million alerts annually regarding potential breaches. Only 10% to 50% of these alerts result in information being sent to probation officers, with nearly half of those leading to no further action.
The NAO report criticizes the MoJ's plan to expand tagging operations, a key component of Labour's strategy to reduce prison populations through community punishments. The MoJ is investing £175 million over three years to expand tagging, with an estimated 22,000 additional people requiring tags annually from 2027. However, the report warns that HMPPS is scaling the service while key elements are not yet functioning effectively, leading to operations beyond stated risk tolerance and increasing the potential for poor performance and threats to public protection.
"Electronic monitoring is central to managing pressures on prisons, but it is not working effectively, creating risks to public protection," said NAO chief Gareth Davies. He emphasized the need for improvements to ensure all intended individuals are monitored and breaches are responded to effectively before further expansion.
Concerns have also been raised about understaffing within the probation service, with an estimated shortfall of around 2,200 probation staff as of March 2026. These issues come in the context of a previous tagging scandal in 2013 involving contractors G4S and Serco, who were found to have overcharged the government for tagging individuals who were already deceased, in prison, or never tagged at all.
A spokesman for the MoJ stated that the government inherited a failing system with record backlogs and has since worked to improve it, with install rates up by nearly 50% since 2024. The ministry is investing £100 million in electronic monitoring, including tagging offenders before release for the first time and strengthening victim protections through new alert systems.