More than 80 prison staff have been fired or reprimanded since 2013 for having affairs with prisoners, statistics show.
Figures from the Ministry of Justice show that 59 female employees and 24 male employees were arrested until last year.
The number of delayed sanctions for “inappropriate behaviour” has risen since 2017 – when female prison staff increased by 27 per cent to 15,000.
It comes after The Sun revealed a crack on Sunday in February Line of dutyThe anti-corruption unit is being “strengthened” to tackle the problem.
Strict prison rules prevent any form of relationship between staff and prisoners and prevent officers from being groomed and corrupted by organized organizations crime gangs.
In some cases, staff who break the rules are fired and possibly jailed.
At HMP Berwyn North Wales18 female staff members were found to have had relationships with prisoners since the prison opened in 2017.
One of the worst prisons was The Mount Prison, in Hemel Hempstead, where six officers were sanctioned for what was described as 'inappropriate behaviour' towards current or ex-prisoners.
Last year, health worker Meghan Woodham, who works at HMP Risley, was jailed for six years after starting an “inappropriate relationship” with inmates drugs King Daniel Doran.
The drug dealer began an affair with Woodham, which allowed him to secure a steady supply of ketamine to feed his drug addiction in prison and organize multi-million dollar drug deals while he served his sentence.
His operation came to light when prison staff became suspicious of his relationship, prompting an investigation by the Prison Service's anti-corruption unit and police.
She was later charged with conspiracy to supply Class A drugs.
A prison service spokesman said the majority of staff are honest and “we are increasingly catching people who are not”.