Trig Points are short, square based pyramids, usually white but that depends on weathering and how many animals have used it as a rubbing post. On the top of the trig is a brass plate with a depression in the middle and three hooped arms. This was used to fix the theodolite when the surveyors were taking their measurements. Another brass plate was fixed to the side on which was marked, O/S/B/M - (Ordnance Survey Bench Mark), and the reference number for the trig point.
In this modern age of GPS, digital mapping, and laser measuring the trig point's role has become obsolete which means many of them are being taken away. This in many respects is sad because not only are we losing a familiar landscape feature we are losing an excellent navigational aid. Those who letterbox will soon tell you that there are hundreds of letterbox sites that have trig point bearings in their clues.
