Amelia Gentleman in the Guardian over a year ago.
"As soon as you enter Wandsworth prison, you notice that dozens of windows on this side of the four-storey A-wing have been smashed. This level of vandalism inside a prison is a bit startling, but it’s such a common problem that prison officers pay little attention to the scale of the damage until asked about it. Each cell window has three narrow transparent panels and most cells have at least one broken pane; prisoners have stuffed duvets and towels into the cavities, or patched them up with flattened milk cartons to keep out the January cold. The prison’s head of security believes that some prisoners are smashing holes in their windows in order to receive deliveries of drugs flown in by drones.
The drone that crashed in December was quite large and carried a camera to help its owner guide it to its destination. The flight was made at a time when the prison is most vulnerable, during the night hours when there are only seven prison officers on duty, responsible for the 1,600 prisoners locked in their cells. Since last February, the deliveries have become a fairly routine occurrence. Several other crashed drones have been discovered on the roof of the prison, similarly loaded with mobile phones and drugs."
She was told that fixing the windows was the job of Carillion.