DUN 25, Former Royal Observer Corps Underground Monitoring Post

The former Royal Observer Corps underground monitoring post, known as 'DUN 25', was built around 1957 for the United Kingdom Warning and Monitoring Organisation (UKWMO). Located near Edzell, this structure is a reinforced concrete bunker with a rectangular plan, featuring two internal rectangular chambers. Access is provided through a metal ladder in a narrow reinforced concrete entrance shaft, which also has above-ground ventilation. The post contains nuclear detecting equipment that was once connected to other monitoring structures above ground.

Above ground, there is a square concrete plinth supporting a raised, square-plan green painted concrete entrance hatch, which has a base course and a bevelled top edge. A metal dome is fixed to the west side of the hatch. A concrete step to the north allows access to the top-opening metal entrance door hatch, leading into the entrance shaft. Inside the shaft, a wall-mounted metal ladder provides access to the bunker. To the north, there is a low, square-plan capped metal ventilation shaft with louvred openings. Between the ventilation shaft and the entrance shaft, a narrow cylindrical metal cover for a survey meter probe and bomb power indicator with baffle plates is located.

Below ground, the interior consists of a large rectangular monitoring room and a smaller chamber used as a toilet and closet near the base of the ladder in the entrance shaft. An iron grill is present on the floor below the ladder. A timber door with moulded surrounds and a vent at the bottom leads into the monitoring room. Small metal piles connect to recording instruments located above ground. Some original timber moulding remains around a notice board and a wall-mounted timber desk, along with wall-mounted communication equipment.