The Tunstall pillbox, coordinates TA 31192 31960, was erected during WWII.
A mark made while the finishing cement was still wet gave the wording, 'C. Nelson Hull', but there was no date. (It is common to find such inscriptions on military structures along the coast.)
The pillbox is entered as RO46 in the English Heritage Rapid Coastal Zone Assessment Survey. RO refers to the civil parish of Roos in the East Riding of Yorkshire, which includes the village of Tunstall. Pillbox RO46 fell over the receding cliff to be in pieces late 2023.
Sharing the same coordinates but having the English Heritage reference RO55, a Royal Observer Corps (ROC) `Orlit’ structure, Type A, was mounted on top of the pillbox in 1951. This was the era of the Cold War. Type A referred essentially to ground or near-ground level installations, as apart from Type B, which were mounted on legs. Orlit Ltd, a construction company specialising in concrete builds, including 'prefabs', or prefabricated housing, ceased to exist when its post-war purpose became redundant. The Orlit was designated Post 18/K.1.
At the end of the same decade, Tunstall was chosen by the ROC as a site for an underground monitoring post, designed to continue functioning in the event of enemy attack. It operated from February 1959 as Master Post 20/T.1 (‘Master’ meant that other posts were controlled from the position) and closed in October 1968, to open once again in 1975 as Post 20/M.2, and be employed until 1991. Listed with the Orlit post as RO55 in the English Heritage catalogue, the bunker was sunk adjacent to the pillbox, which subsequently served as a restroom.
To estimate how far the bunker was from the cliff when installed, firstly a look at Erosion Post data, from 1959 to 2010 (52 years), the latter date being the end of EP measurement. EP77 is 186.98 metres north of the pillbox site, and EP78 is 254.02 metres south of it. EP77 records 76.35 metres of cliff lost between the above dates, EP78 returns 74.44 metres. An average to work with might be 75.40 metres.
Secondly, the current profiles system of measurement. Profile 81 intersects the cliff line 61.22 metres north of where the pillbox used to be. From 2011 to spring 2025 (14 years), cliff loss here is 34.51 metres. 75.40 + 34.51 = 109.91 metres. Bear in mind that this distance pertains only to the bunker.
Distance of the original pillbox from the cliff when erected would of course be greater. Assuming the pillbox predates the bunker by 16 years, a back projection at 1.67 metres loss per year (109.91/66) is 26.64 metres. 109.91 + 26.64 = 136.55 metres.