Who said the SAS feed only on enemy sentries and terrorists? Rowdy prisoners can occasionally form part of their diet as well and prison riots can also be the SAS’s playground.

Scotland, 1987.

Thirty years ago, a prison riot in Peterhead had turned ugly. Fifty inmates had managed to take control of D-wing. The riot had begun with the stabbing of an officer, but it had quickly escalated in a hostage situation. Two wardens were taken hostage. One of them 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.

Peterhead Prison was infamous for its Victorian workhouse conditions. Electricity in the cells was limited, the food was awful, and the drainage horribly unsanitary.