AN urgent investigation was under way last night into security at a hospital after drugs were stolen from an operating theatre.

Police and bosses at Middlesbrough's James Cook University Hospital are looking into the theft of ampules of a powerful painkiller.

A police spokeswoman said five ampules of liquid Fentanyl were reported missing by staff late on Wednesday.

She said: "The drugs are used in pain relief and could be harmful if taken unsupervised."

Richard Clayton, of the hospital, said last night: "We can confirm five ampules of Fentanyl were stolen from the emergency operating theatre area at The James Cook University Hospital late yesterday afternoon, and a full internal investigation has been launched.

"Fentanyl is regularly used as pain relief in operating theatres and is a controlled drug.

"We view this as a very serious incident and are working closely with the police."