THE public will be put at risk under government plans for a mass expansion of electronic monitoring to tackle prison overcrowding in England and Wales, Britain’s spending watchdog warned today.

The National Audit Office (NAO) said that the system is already under significant strain and would need to be upgraded before it is extended.

NAO chief Gareth Davies said: “Electronic monitoring is central to managing pressures on prisons, but it is not working effectively, creating risks to public protection.

“The Ministry of Justice (MoJ) and HM Prisons and Probation Service should address the inefficiencies and risks identified in our report before expanding electronic monitoring.”

Prison Officers’ Association (POA) assistant general secretary Terry McCarthy told the Star: “Today’s revelations expose a tagging system in crisis, reflecting years of under investment in a failing criminal justice system.

“The government must stop burying their heads in the sand and address the very real problems that face the whole of the criminal justice system.”

The number of people in England and Wales being electronically monitored has doubled to 28,700 over five years and is estimated to rise to 22,000 tagged each year from 2027 under the government plans.

But the NAO found that just 62 per cent of tag requests between January and April were successfully installed within the standard two attempts for adults, with an estimated shortfall of about 2,200 probation staff as of March.

The Howard League for Penal Reform said that unchecked prison overcrowding has led to ministers “putting their faith in a flawed electronic monitoring programme that has expanded rapidly and is about to spread even wider.”

Chief executive Andrea Coomber KC said: “There is overcrowding in probation, just as there is overcrowding in prisons, and public safety depends on this shift being properly resourced and effectively managed.”

Prison Reform Trust chief Pia Sinha said: “Expanding the use of tagging without addressing wider pressures risks undermining both public confidence and public safety.”

National justice reform charity Revolving Doors warned the mass rollout of tagging “simply opens up another avenue for chaos.”

An MoJ spokesperson said that the government had inherited “a failing tagging system with record backlogs” and noted that install rates had risen by almost 50 per cent since 2024.