Sheppey’s Swaleside prison recorded more disciplinary incidents than any other prison in the south east last year.

According to Ministry of Justice (MoJ) figures obtained by the Howard League for Penal Reform, the jail has become progressively worse for inmate behaviour over the past four years.

The MoJ describes “concerted indiscipline” as involving two or more prisoners acting together to defy a lawful instruction or against the requirements of the regime of the establishment.

This includes outbreaks of violence, such as a riot, and involves drafting in officers from other parts of the prison or outside to deal with it.

Last year, the Category B Swaleside prison recorded six such incidents – more than any other jail in the whole region.

Data also shows these types of occurrences have been steadily rising since 2012, when there were two recorded, followed by three in 2013 and four in 2014.

In total, there were 33 concerted indiscipline incidents in all prisons in the south east last year and 87 in the last three years.

Nationwide, there were a total of 282 incidents during 2015 – an average of more than five a week.

In a bid to what it said was to obtain a better understand the scale of the problem, the National Offender Management service introduced an “enhanced incident reporting standard” last summer.

The Howard League’s chief executive, Frances Crook, claimed the figures provided evidence the whole prison system was failing.

She said: “This is a symptom of the problems in prisons which are grossly overcrowded, understaffed, and where violence and self-injury and assaults on staff and on other inmates is endemic.

“Evidence shows that building additional prisons only compounds overcrowding and its consequent problems as the courts send more people to prison every day.

“We cannot go on cramming more people into jails without any thought for the safety of staff, prisoners and the public.”