An investigation is under way after a remote controlled helicopter, which is believed to have contained drugs, crashed at Wheatfield Prison in Dublin.
The drone crash landed into an exercise yard at the prison at around 11am yesterday morning.
A package containing suspected drugs was attached by a rope to the four-bladed device, which hovered over the yard, while up to 20 inmates gathered around it in the botched attempt to bring in contraband.
However, the drone got caught on anti-helicopter wires, in place to prevent any airborne escape attempts and crash-landed into the complex.
"This isn't a toy," said a prison source.
"It was a high spec drone with a high spec camera through which the operators could monitor the route it was taking.
"They wouldn't have intended to land it in the prison, just hover over it until the inmates got their hands on the contraband."
A digital memory card onboard the mini-helicopter recorded the exact route the device took and also shows the smugglers carried out a trial run before the failed attempt.
"They definitely had done their homework on this," said one source.
A number of prison staff noticed the commotion as the device crash landed and intercepted the operation.
The Irish Prison Service confirmed that a number of prisoners will face disciplinary procedures following the incident.
It is understood some of the material recovered from the drone was ingested by one of the prisoners.
He has been put in solitary confinement under 24-hour watch until the contraband is retrieved.
The drone was seized and handed over to gardaí.