DUN 25, Former Royal Observer Corps Underground Monitoring Post

Circa 1957, former Royal Observer Corps underground monitoring post constructed for the United Kingdom Warning and Monitoring Organisation (UKWMO), officially known as 'DUN 25'. Situated near Edzell this reinforced concrete monitoring post comprises an underground rectangular-plan bunker with two internal rectangular chambers, accessed via a metal ladder in a narrow reinforced concrete entrance shaft. There is above ground ventilation. The structure contains nuclear detecting equipment formerly linked to other detecting structures above ground.

Above ground there is a square concrete plinth on which sits a raised, square-plan green painted concrete entrance hatch, with a base course and bevelled top edge. There is a metal dome fixed to the west side of the hatch. There is a concrete step to the north providing access to the top-opening metal entrance door hatch which leads to 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 and capped metal ventilation shaft with louvred openings. In between the ventilation shaft and entrance shaft there is a narrow cylindrical metal survey meter probe cover and bomb power indicator with baffle plates.

Below ground, the interior (seen in 2013) consists of a large rectangular-plan monitoring room with a smaller chamber for use as a toilet and closet near the base of the ladder in the entrance shaft. There is an iron grill to the floor below the ladder. A timber door with moulded surrounds and a vent to the bottom leads to the monitoring room. A number of small metal piles lead to recording instruments located above ground. There is some surviving timber moulding surrounding a notice board and wall mounted timber desk, including original wall- mounted communication equipment.