CART catches up with the team at US podcast @HomeBrewHistory to introduce to those across the pond to the remarkable Auxiliary Units and Special Duties, and to dispel some myths about Britain’s unpreparedness in 1940.
One of our main aims for the new website was to get as much information on individuals was possible, including images. A good example is that of Airlie Abinda Campbell a member of the Special Duties ATS.
One of the most remarkable stories associated with Airlie, is how she met her husband, George Gascoyne (https://www.staybehinds.com/george-archibald-clive-gascoyne) an Auxiliary who accidentally stumbled across Airlie’s wireless bunker, descended down the ladder and was confronted by her pointing a revolver at his head (photo attached of their wedding day)!
If anyone has any images of any other ‘Secret Sweeties’ (what the members of the Special Duties ATS unit were, rather politically incorrectly called), we would love to see them.
Indeed, if anyone has any information on the Special Duties branch we would love to hear from you!
We must be now very near to losing all members of the Auxiliary Units and Special Duties, but we are more determined than ever to remember them and the sacrifice they were willing to make for the country.
When looking at an Operational Base, a plan can helpful to understand what can be seen in specific photos. It is often difficult to understand a structure from a single image or series of images. But a plan, or series of plans, can only show two dimensions at once.
The simplest way to address this is with a sketch, that adds the third dimension. Our Admiralty 4 (Prior Park) Patrol report contains an example of this. The sketch makes clearer how an underground structure is arranged, when that cannot be easily seen from the images alone.
Software has made it possible to build virtual 3D models from measurements of an Operational Base. Once the realm of specialists, there are now entry level software options to build a virtual 3D model and colour it to create an accurate reconstruction of an OB that may be collapsed or overgrown. An example of this can be seen with theseimages of a very overgrown OB at Portesham in Dorset, with a simple 3D model showing much more clearly than any of the image the layout of the operational base.
We have been fortunate enough to have a professional showing us how it should be done. Matt Brazier kindly produced a couple of models of Operational Bases for CART and has animated these into a walk through which further improves the understanding of design. We have seen his model of the Salisbury In-station already. He produced another of Operational Base of the Drellingore Patrol. The OB in this instance was collapsed, though the shaft and escape tunnel remain intact. The reconstruction video allowed the original structure to be visualised as it would have been. There is always a risk of introducing interpretation into a model and making assumptions. The initial model of the Binnegar OB seen in the report, assumed the shaft was a rectangle shape. However, once excavated it became clear it was narrower at one end than the other, as can be seen in the images. Experience has shown that you can’t take too many measurements and it is is also worth planning a follow up visit to repeat the measurements that were overlooked the first time!
More recently archaeological recording has advanced to incorporate 3D scanning technology. Issues of missed measurements are overcome as the laser scanner takes thousands of measurements to create a point map. This plots each measurement in three dimensions to create a virtual model of the structure. This model can be rendered with either illustrations or photographs mapped onto the images. Recently, AOC Archaeology were contracted by Forestry and Land Scotland to record an Operational Base that came to light during felling works. This was an OB in a relatively good state of preservation, belonging to the Beattock Patrol in the Scottish Borders and ideal for this technique. Of particular interest was the linking of scans above and below ground to generate an illustration of the location of the structure in the landscape. As these structures are vulnerable to rust and other natural damage over time, this has to be the modality of choice to record these structures where possible. We are grateful to AOC for sharing the final report and the images. These images are very effective and certainly captured the imagination of the press, resulting in numerous articles including one in French!
Investigating buried structures using geophysical techniques has been increasingly common in recent years. It allows large areas to surveyed relatively quickly and uses differences in the responses generated by the buried archaeology and natural or fill materials to locate structures and identify their extent. If you have ever been confused by what it involves, Historic England have a straightforward explanation in their guide to research techniques.
The use of such techniques on Auxiliary Sites has been relatively limited. This may relate to the belief that the sites are identified and not recognising that elements of the structure may extend beyond the immediately visible OB, as we saw with the ventilation systems at Binnegar and Bromyards Downs in previous pages. Many structures are in woodland, where the application of the techniques are more difficult.
At Coleshill, a metal detecting survey and magnetometer was used to identify metallic targets for investigation. A ground penetrating radar was briefly trialed over the known demonstration Operational Base at Coleshill House and showed that it was detectable to the technique.
Subsequently a formal magnetometry survey was conducted by the short lived Churchill’s Underground War Group, at Langrish House in Hampshire, in an attempt to identify a possible Operational Base in the grounds. Nothing was found though documentary evidence has subsequently suggested the OB was elsewhere.
The Buckland St Mary In-station was known to have been built at Castle Neroche. The Castle was an Iron Age Hillfort converted into a Motte and Bailey Castle during the Anarchy period. Sergeant Arthur Gabbitas who documented the role of his Royal Signals colleagues in the Auxiliary Units Special Duties Branch was stationed there for a while. He left a brief description of the site. Historian and former Royal Signals Officer, David Hunt, visited the site in 2008, obtaining a useful first hand account of the location of the Operational Base, a “Zero” station for the the Chirnside Network, from a local resident who remembered it. His account included the presence of ventilation pipes showing like rabbit holes in the side of pits in Castle grounds. No remains could be found at the time but the site was recorded on the Somerset Historic Environment Record. There are separate records for the above ground Met Hut, which David remembered as still present during his own childhood visiting the site, and the Operational Base.
In 2017, CART arranged a visit to the site, to see if any evidence remained. David’s reports provided a focus for the search. The Met Hut base was measured and photographed. The location of the door could be identified. A search of the surrounding area found a small fragment of wire on the adjacent bank, twisted as if to connect to a terminal, perhaps for a battery. At the location identified for the Operational Base, fragments of glazed earthenware pipe were found, a feature often seen at such sites. A very careful search found a small hole near the edge of the bank with the top of two earthenware pipes just visible at its base, just a few centimetres below ground level. The earth had washed down into the pipes over the years, creating the hole. The pipes were almost certainly part of the ventilation system previously noted. Nearby an aerial tree was identified with fragments of the aerial feeder cable projecting from the bark. Because the entire site is a scheduled monument, no excavation of any sort was possible.
A report was prepared and submitted to the County Archaeologist who fortunately was interested enough to arrange for a further non-invasive investigation after obtaining the necessary permissions. Liz Caldwell from GeoFlo (www.geoflo.co.uk) was commissioned by the Southwest Heritage Trust, which was organised by Chris Webster, to survey the site. We think that this report represents the first time that an Operational Base was located by such techniques. With permission we include images from this report in an album of images form the site. The survey was conducted with a Fluxgate gradiometer (Bartington Grad 601-2 ) and Resistivity meter (TR/CIA Resistance Meter) processed with Geoscan Geoplot 3.00v software. The survey showed with a high degree of confidence the location of a structure underground, with a high magnetic signal, consistent with an elephant shelter structure. The ventilation pipes were not visible using these techniques.
On a repeat visit visit to the site, with a change in the conditions, a very shallow regular depression could be identified at the site identified by the non-invasive techniques. A further hole with a pipe junction was identified, in line with the first, supporting the interpretation of a ventilation system. Two aerial trees were identified. We do not believe there is a third extant tree at the site, though there is another tree with a lightning scar, an appearance that can look similar to an aerial scar. As both aerial trees and lightning strikes are located on high ground they can exist in close association.
Coming right up to date, a group from Keele and London South Bank Universities have published a pre-print paper utilising several techniques, namely, Ground Penetrating Radar (GPR), Resistivity, Conductivity and Metal detecting across three Operational Base sites, one intact, another collapsed and a third destroyed to test the modalities. Metal detecting proved valuable in locating the site of the structures, with GPR showing extant chambers and depths. The other modalities also produced useful information and allowed the construction materials to be identified. This is an interesting proof of concept study and suggests that the study of buried structures of the Auxiliary Units with non-invasive techniques is both useful and practicable. We look forward to further investigations of this nature.