Stangmoor Prison was a prison in England.
Before becoming a prison it was a fortress in the Middle Ages. It was the ideal place to demonstrate the Keller Machine, as there were many criminals available. Later, when the Master and his band of convicts took over, it was used as base of operations for the plan to hijack the Thunderbolt missile. UNIT administered it for a time after it was retaken from the convicts. (TV: The Mind of Evil) Prior to his death, General Andrews was the prison's governor. (AUDIO: The Last Post)
After his capture and trial, the Master was sent to Stangmoor Prison, but during his captivity, an army of hypnotised salespeople stormed the prison, to try and rescue him. However, this failed and the Master was sent to another secure holding facility. (PROSE: Freedom)