Obiter once saw a robot prison guard demonstrated in the US. The Dalek-like contraption was deployed in earnest only once, to get CCTV footage of a prison riot. Not surprisingly, it was a one-way mission.

That was 20 years ago, and it seems the technology has marched on considerably. The latest effort is from the Republic of Korea, where three rather more sophisticated robot wardens are to undergo a month-long trial at a jail in the eastern city of Pohang next year. The 1.5-metre-high machines move on four wheels and are equipped with cameras and other sensors that allow them to detect risky behaviour.

Given recent Korean successes with high technology and the prospect of a winter of public sector discontent, Obiter advises the Prison Officers Association to keep a very close eye on upcoming Home Office procurements.