In one case, a mother and her 12-year-old daughter were pulled over in their car by two criminals who inserted drugs into the girl and threatened them to pass the drugs over during a prison visit.

Prison bosses are so concerned at the problem, and drug-smuggling generally, that they have set up a confidential phone line to encourage people to supply them with information.

At the launch of the helpline, the Irish Prison Service disclosed:

Mobile phones — as small as USB keys and key fobs — are rented out for as much as €1,000 to inmates;

Drugs are worth around five times more inside prison than on the street;

Prison gang bosses operate a sophisticated external payment systems — including bank accounts and postal addresses — where inmates pay for drugs and phones through family or friends;

Family members — parents, siblings; and children — pay the consequences if an inmate fails to pay debts or smuggle in drugs;

70% of offenders coming into prison have a drug addiction.

IPS figures show there were 1,000 drug seizures in 2013, 986 in 2014, and 418 so far this year. Some 805 mobile phones were seized in 2013, 728 in 2014, and 332 up to 21 June this year.

“One of our biggest concerns is the use of children for smuggling drugs into prison, that is when children are used to bring drugs internally,” said chief officer Ben Buckley of the IPS Operational Support Group.

He said the drugs are “hidden so well” that the children pass the screening process and the drug dogs undetected and into the visiting rooms.

“They are reproduced on the visit by the persons carrying them. They basically remove them from the person.” He said “every orifice” is used to hide the drugs and that the removal of drugs can be graphic.

“Unfortunately you have some minors that are almost trained and coached in how to get drugs into a prison,” he said. “One could say they are doing it voluntarily, but they are children.”

He said this was happening across the prison system.

However, they were now seeing cases where gangs were forcing mothers and their children to carry the drugs into prison.

“We had a case last year where a 12-year-old child and her mother were on their way to prison,” he said. “The car was pulled in and two people intervened. They inserted the drugs inside the child. She was brought into the visit by her mother. The mother removed the drugs and handed them over.”

IPS director general Michael Donnellan said packing drugs internally “can have devastating effects”. He said inmates and their families were under “enormous pressure” to bring drugs, as well as weapons and phones, into prison.

Confidential phone line: 1800 855 717