Onley Prison inmates were handed an extra 14 years behind bars for breaking rules last year, figures reveal.
Prison reform campaigners say imposing extra jail time as a punishment simply worsens overcrowding, and have called for it to be scrapped as a punitive measure.
Ministry of Justice data shows that prisoners were handed 5,214 extra days behind bars in 2018-19.
The additional time was distributed across 350 judgements, meaning 15 days were handed out each time on average.
The type of offence for which prisoners got the most extra time was unauthorised transactions, which include those for alcohol and drugs – prison officials doled out 4,151 days in total for the transgression.
Unruly convicts were also slapped with extra days for disobedience or disrespect, and violence.
Prisoners at Onley received 13% more additional days than the previous year – 4,620 were imposed in 2017-18.
The increase reflects the trend across England and Wales, where prisoners were given around 388,000 extra days in 2018-19 – 9% more than the previous year.
Frances Crook, chief executive of the Howard League for Penal Reform, said the growing use of repeated punishment in prisons is a symptom of a failing system.
“Imposing additional days of imprisonment does not work,” she added.
“Rather than solving problems, it creates new ones, piling more pressure on the prison population and worsening overcrowding, which in turn leads to more drug abuse and violence.
“Scrapping the imposition of additional days would make prisons safer, fairer and less likely to churn out people who go on to reoffend in the community.”
Peter Dawson, director of the Prison Reform Trust, said many of the punishments will have followed offences borne out of boredom and frustration.
He added: “Overcrowded prisons with under-occupied prisoners feed this self-defeating use of a penalty that ultimately just makes the problem worse.
“The prison service knows that incentives do more to change behaviour than punishments, and our consultation with prisoners confirms that. It’s time to turn policy into reality.”
A spokesperson for the MoJ said: “Having robust punishment available is essential to running a safe prison, so it is absolutely right that anyone who attacks a fellow inmate or smuggles drugs or phones should face longer behind bars.”