Prisoners who broke the rules at Flockton’s New Hall jail got hundreds of extra days behind bars.
And they joined hundreds of prisoners who got more than 10,000 days of additional imprisonment imposed on them in Yorkshire jails last year.
A report published by the Howard League for Penal Reform reveals that nationwide the total number of additional imprisonment imposed during 2014 was almost 160,000 days – or 438 years.
New Hall houses female prisoners with an average of 400 locked up at any one time.
Disciplinary hearings there handed out an extra 934 days.
Leeds Prison had 260 extra days while Wakefield’s top-security jail handed out an extra 368.
The hearings, which cost between £400,000 and £500,000 a year in total, mainly concern disobedience, disrespect or property offences, which increase as prisons lose control under pressure of overcrowding and staff cuts.
A prisoner found guilty at an adjudication can face punishments ranging from loss of canteen to solitary confinement and extra days of imprisonment.
The report reveals that the number of adjudications where extra days could be imposed has increased by 47% since 2010.
The number of extra days imposed on children has almost doubled in two years – from 1,383 in 2012 to 2,683 in 2014 – even though the number of children in prison has almost halved.
The rise in the number of adjudications has come at a time when prisons across England and Wales are struggling to overcome problems caused by a growing prisoner population, chronic overcrowding and cuts of almost 40% to frontline staffing.
Frances Crook, Chief Executive of the Howard League for Penal Reform, said: “The system of adjudications has become a monster, imposing fearsome punishments when people misbehave often as a result of the dreadful conditions they are subjected to.
“This bureaucratic, costly and time-consuming system of punishments then further feeds pressure on the prisons, creating a vicious cycle of troubled prisons and troubling prisoners”.