A drone has been found in the grounds of Norwich prison.
HMP Norwich staff discovered it on 27 August near huts where visitors are scanned before entering.
Prison officers searched the perimeter fence in the hope of finding its operator, but without success.
A Prison Service spokesman said: "At no point was the security of the prison at risk and there was no wider disruption to the establishment. It was not carrying any contraband."
He added: "It has been confiscated by the prison."
Norfolk Police said officers were told of the discovery but it was a matter for the Prison Service.
In March this year a drone, or UAV (unmanned aerial vehicle) was used to try to smuggle a package into the grounds of Bedford Prison.
But the drone was intercepted by staff.
Anyone caught using a drone in an attempt to smuggle contraband into a prison faces a prison sentence of up to two years.
HM Prison Norwich is a Category B/C facility and has occupied its current site since 1887.