Who said the SAS feed only on enemy sentries and terrorists?

Rowdy prisoners can occasionally form part of their diet as well.

Scotland—1987.

30 years ago, a prison riot in Peterhead had turned ugly.  50 inmates had managed to take control of D-wing.  The riot had begun by the stabbing of an officer, but it had quickly escalated in a hostage situation.  Two wardens were taken hostage.  One of them, however, was released because of wounds; the other was about to endure a five-day ordeal that would only end with the storming of the black-clad SAS troopers.