I noticed this the other day and it wouldn’t surprise me to realise I’m probably in the minority, not knowing what it was. I’m amazed I haven’t seen one before, maybe I have and it didn’t register, but anyway thanks to good old Google I now know it’s a triangulation pillar used originally as a surveying station for improved and accurate map making and built by the original Ordnance Surveyors.
Apparently 2016 was the 80th anniversary of the first ‘trig pillar’ being used in Northamptonshire. Hundreds have been lost from the initial number of well over 6,000, due to factors such as coastal erosion and development of the land. Nowadays they’re mostly used as navigational aids.
This beautiful image (courtesy of Fotolia) is a trig point on Little Solsbury Hill overlooking the city of Bath.