Ministry of Justice figures show a drop of more than 1,700 prison officers in total across the eight highest security prisons

High-security prisons holding Britain’s most dangerous prisoners have lost one in four officers since the Conservatives have been in government, it can be revealed.

HMP Belmarsh, the category-A men’s prison that has inmates including serial killer Stephen Port and extreme Islamist preacher Anjem Choudary, has experienced a near 40% drop in prison officer numbers – from 891 in 2010 to just 553.

I entered the prison system 60 years ago. It’s never been so chaotic and dangerous | Eric Allison Read more

The Ministry of Justice figures, which show a drop of more than 1,700 prison officers in total across the eight highest security prisons, come as new data was released showing assaults and self-harm at record levels in jails.

Other high-security prisons that have seen a significant drop in prison officer numbers include Long Lartin, where inmates rioted earlier this month. The 622-capacity category-A jail, where there have been four homicides in the past four years, has lost almost 200 prison officers since 2010.

After the riot in the prison, the Prison Governors Association said the disturbance should be “ringing alarm bells at the most senior level” and called it symptomatic of cutbacks in the prison service management structure.

The figures came to light in a parliamentary question tabled by Labour MP Toby Perkins, who said the steep decline in the number of officers, particularly in high-security prisons, meant prisoners were “spending their whole sentences locked up and crucial opportunities for rehabilitation [were] being missed”.

He said: “The scale of these cuts to the numbers of officers, charged with looking after Britain’s most dangerous criminals, is appalling. It puts into context the riots, suicides and disorder that has terrorised Britain’s prisons this summer.

“The public rightly expect that government will take seriously their duty to protect us and to rehabilitate prisoners and these figures demonstrate that they are failing that basic duty.”

In his response to Perkins, the justice minister Sam Gyimah said the government had committed to recruit a net increase of 2,500 prison officers by December 2018. “In addition to the recruitment activity to fill these 2,500 new posts, there is ongoing recruitment activity to fill current vacancies, and vacancies which arise due to retention rates of existing staff,” he said.

Jackie Marshall, of the Prison Officers Association, said staff shortages were costing the taxpayer more and putting officers at risk. “When there’s fewer staff, we don’t get a change to talk to prisoners, which means we’re less likely to hear about any disturbances,” she said.

“Prisoners spend longer in their cells, which makes for a tense environment and it does make it more dangerous because there are fewer colleagues to protect you. It’s also costing a fortune because staff shortages in the south-east mean there’s currently up to 200 officers living in hotels to cover places that are understaffed.”

The latest Ministry of Justice figures on violence in prisons in England and Wales, released on Thursday, showed a record high of 27,193 incidents until June. Assaults on staff were also at a record high – up 25% on the previous year – and over the same period, self-harm in prison also rose to record levels.

The number of prisoner-on-prisoner assaults was also the highest recorded since the data series began, at 19,678.