The bunkers or hideouts used by the Auxiliary Units were officially known as 'Operational Bases' ('OB'). The word 'hideout', the officers who ran the Resistance soon decided, suggested a more passive purpose than that for which these bases had been constructed, and if overheard by the Germans or their friends, would not alert them to their intended use.
Auxiliary Units hideouts were supposed to be merely the places to which Resistance men could withdraw to eat, sleep and lie low. However, some of the first hideouts in Kent appear to have been built with sieges in mind, for they had their own early-warning outposts several hundred yards away, connected to them by hidden telephone wires. And several of the hideouts in Kent were, like the one entered through the sheep trough, built primarily as lookout points.
By the end of 1940 about 300 OBs were already in use around the country, and another 61 were ready by the spring of 1941. There were some 534 by the end of that year, and although no later figures are available, upwards of a thousand existed at the time that the Auxiliary Units Patrols were disbanded. No two were identical, but most were eventually made large enough to house six or seven men in reasonable comfort, although many at first were little more than fox-holes with log roofs, so badly ventilated that candles sputtered from lack of oxygen and the men who tried sleeping in them all night awoke with headaches. Each hideout was eventually fitted with bunks, cooking stoves, Tilley lamps and other comforts provided by the Army, and each was stocked with food and water - in some cases sufficient to sustain a patrol for as long as a month. Wherever dampness was a problem the tinned foods were frequently replaced so that there was never a chance of besieged Patrols being finished off by food poisoning. Most hideouts had plenty of room for the Patrols' arms, ammunition and sabotage material, but in some areas subsidiary hides were dug near by to hold these and additional stores of food. Many of the hideouts eventually had chemical lavatories, and a few even had running water and some rudimentary form of drainage. The hideouts were so well concealed that anyone walking over them would not notice that the ground beneath their feet had been hollowed out, or that it was unusual in any way. And of course the hideouts had to be made impossible to detect from the air.
Undoubtedly the greatest problem was that of digging the hideouts without anyone noticing - not even the members of neighbouring Patrols. In most of the coastal areas the first hideouts had to be dug by the Auxiliers themselves, stumbling around late at night and in total darkness. Incredibly, they usually managed to finish the job unnoticed, but anyone who happened across a half-completed hideout had to be fobbed off with some sort of story that would put an end to questions. The usual cover story was that the hole 'was being dug for the storage of emergency food supplies for a secret government department' - a story that did not make much sense at the time but did stop people asking questions and usually stopped them talking. Speculation about the 'food stores' still continues in some areas of Britain today, and there are dark rumours about how 'They' were going to look after themselves all right.
Another major problem which faced the men who built the hideouts was that of disposing of the subsoil which they had brought up. Carting this away in the dark was no easy task, especially when one remembers that a cubic foot of earth weighs just over a hundred pounds, and the average Resistance hideout in Britain was about twenty feet long, at least ten feet wide, and always high enough for its occupants to stand erect in it.
Many of the methods which were worked out for scattering the spoil in Kent was taken up in other counties, but each new hideout presented new problems. Sometimes the men simply scooped away topsoil in a wood, replaced it with the spoil from their hideout, covered this with the original topsoil and laboriously replanted all the undergrowth. In Devon and Cornwall they sometimes carried out the spoil a bucketful at a time and poured it into streams. At Wickhambreaux in Kent, near the mouth of the River Stour, earth from an Auxiliary Units Patrol's hideout was moved across the river on an aerial ropeway and added to a fill that had been begun by the Kent River board as an anti-flood barrier long before Auxiliary Units people appeared on the scene. Not far away, in Stocking Wood, near Baddlesmere, about three miles south of Faversham, the chalky sub-soil was so hard to hide that Norman Field hit on a particularly ingenious solution to the problem. He told his men to put the subsoil in a natural hole in the wood, and he used a camouflet set to mine it. He then placed a line of the sets across the wood and, the next time German bombers flew over, detonated all the charges. What followed looked and sounded like a stick of bombs exploding, and no one questioned the appearance of the chalky craters in the wood.
When Captain Field decided to place an underground observation post on the bare crest of Charing Hill, at a point that could be seen from all directions, he had to solve both the problems of surreptitious digging and soil disposal. After giving the matter a lot of thought he and his men borrowed an anti-aircraft gun, placed it on the spot they had picked for their observation post. and then started filling sandbags to shield it, using for this the earth that they scooped from around the base of the gun. Then, shielded from view by the sandbags, they finished digging the observation post and camouflaging its entrance. For several weeks they manned the gun, and then an Army truck came to tow it away and to cart off the sandbags. This in itself was not unusual, for the guns were often moved from one place to another. All that remained on Charing Hill was a perfectly concealed hideout.
The Patrol members for various reasons did not always dig their own hideouts. In several areas they were dug for them by members of Royal Engineer tunnelling companies or simply by ordinary Sappers, and the men in the patrols dug only the entrance tunnels. When the hideouts were dug for the patrols by the soldiers who had been sent from Coleshill to train them, these troops made the entrances, too, and the men who were to use the hideouts were taken into their vicinities and told to find them. This they never did.
In at least one instance civilian labour had to be contracted to produce some hideouts. This happened on the Romney Marsh, where the hideouts were sited below sea-level and only experts could do the sort of concreting that would result in water-tight construction. In those days navvies in provincial areas were rarely transported great distances to their work, but the ones who built the hideouts on the Romney Marsh were brought in from the other side of Kent - and were never given the time to learn their way around the area, so that probably they would not have been able to find their ways back to the hideouts again.
Flooding was a problem in other places as well. On the Essex Marshes, just west of the Blackwater, several Patrols each dug and provisioned four successive hideouts, each time hoping that they had at last beaten the problem of flooding, and each time finding that they had not.
Not all the hideouts were fresh excavations. One of Peter Fleming's best was an enlarged badger sett on the edge of a chalk pit at Challock, seven miles south of Faversham, Kent, and another had been the cellars of Evington Manor, at Hastingleigh, near Wye, long before destroyed by fire. The members of one of Reginald Sennitt’s Patrols on the Essex Marshes who suffered repeated floodings finally recalled that an isolated farmhouse on high ground in the area had a cellar which had been scaled off from the house itself for many years. And so instead of digging themselves yet another hideout, the Patrol's members tunnelled from a briar bush several hundred yards from the house into the cellar which, as they had hoped, was completely dry. At no time did the two elderly women who lived in the house have any idea of what was going on down below.
The so-called smugglers' caves along the coasts of Devon and Cornwall were unacceptable as hideouts because they were so well known and were always, even during the war, likely to be visited by tourists. Certainly the Germans would have had no trouble pinpointing them. However, on the Isle of Thanet in Kent the tunnels and underground rooms believed to have been carved in the chalk in the heyday of smuggling are less well known, and the Thanet Resistance group headed by a Manston Grove farmer, Norman Steed, turned several of the excavations into excellent hideouts. When he discovered an old tunnel that reached from the edge of Manston Aerodrome (at that time one of Britain's most important RAF advance fighter stations), right under the runways, he called in his Intelligence Officer to explore it with him. Fifty yards along the tunnel they came to a fall that blocked it completely, and the officer decided to send in a team of Sappers to dig it out. Cleared, the tunnel would provide Resistance saboteurs with a perfect way in and out of the aerodrome. However, before the Sappers began their work a stray German bomb landed in the middle of the airfield; the only damage it caused was to block the tunnel permanently.
In Wales abandoned coal mines, forgotten even by most of the miners, were turned into excellent hideouts. The Welsh Resistance men, although friendly enough with the English and Scots they met at Coleshill, were reluctant to show their hideouts to Intelligence Officers from the headquarters, and they would not unless flatly ordered to do so. Yet these Welshmen were certainly not all recluses; one had been a rugby international and had been capped for Wales about fifteen times, another had been champion grenade thrower of the BEF in the First World War, and yet another had won the Victoria Cross in that war. But the Welsh, like the Resistance men on the Isle of Wight, hated sharing their deepest secrets with 'foreigners'.
Mine workings were also used as hideouts by Patrols in other parts of the country-coal mines in the North-cast and, in Cornwall, abandoned tin mines nearly a quarter of a mile deep and in constant danger of caving in because their timbers were rotting, and in which echoed the angry roar of subterranean streams.
In both Cornwall and Scotland, old ice houses and ice pits were taken over and made habitable hideouts, and in the north of Scotland several 2,000-year-old Pictish dwellings were used. Known only to the shepherds, each of these underground dome- shaped rooms had to be entered through a hole in its top which was covered with a weathered stone. All these dwellings needed was a good sweeping, and after the war they were simply abandoned.
One of the most spectacular hideouts built in Kent by Peter Fleming was intended not as a base for a single Patrol but was to be a collecting point for stray Resistance men on the run. It contained food, water and sleeping accommodation for about 120 people. Nor was the sheer bulk of this hideout its only unique feature. Fleming had discovered a boat-shaped depression in King's Wood, in a cleft in the hills above The Garth, about sixty feet long, thirty feet wide and thirty deep. Local people told him that this hole had been dug during the First World War as a landing place for an airship. Whether or not this was true, Fleming reasoned that the last place the Germans would look for a secret hole in the earth was underneath a well-known one. He therefore had the bottom scooped out of the airship hole, built a shelter in it, and the earth was replaced.
Any entrance into this hideout through the airship hole itself would have been conspicuous, especially after 120 people on the run had trampled a fresh path down into it. Fortunately an old footpath happened to run alongside the hole, about fifteen yards away from its rim. On the edge of this path Fleming had his men dig a vertical shaft to the depth of the shelter's floor, and a low tunnel was cut between the two. The trapdoor for this entrance was a tree trunk nearly six feet high and weighing about half a ton. It was fixed into place so that when 'unlocked' it could be swung aside at the touch of a finger. The underground counterbalances that supported this lid were later duplicated in several other areas.
Another of Fleming's hideouts on the North Downs in Kent had an even more ingenious method of approach. Anyone wishing to use it had first to find a marble that was hidden in some leaves near by. This then had to be inserted into what appeared to be a mousehole. The marble would roll down a pipe about twelve feet long and plop into a tin can, a signal to the men inside that they should open the trapdoor. The trap itself was concealed in the gnarled, ivy-covered roots at the base of an ancient tree.
Another hideout near Wootton in Kent, just south of the junction of the Dover and Folkestone roads, was built in 1941 by a company of Welsh miners. It was entered through the false bottom of a manger against the side of a hill. Yet another in Kent was under a brickyard at Lydden on a site now occupied by an industrialised housing estate. It was entered by moving away a section of what appeared to be a solid wooden wall. But the most common trapdoors on the hideouts were simply oak or elm boxes filled with a foot-thick layer of earth. Most of these trapdoors had to be lifted out, and to make this easier, many of them were mounted on steel springs that, when a hidden catch was pushed, raised the tray enough for a man to get his fingers under its rim. All along the coasts of Britain many hideouts could be entered through what appeared to be cucumber frames, often with the plants actually growing on the trapdoors. One hideout in Scremerston, in Northumberland, just south of Berwick-on-Tweed, was entered through a wood-pile; the right twig had simply to be tweaked and an entire section of the pile would slide away. Peter Fleming's badger sett was entered by lifting the rotting remains of what had been a farm cart which long ago had lost its wheels. Because the cart body was so heavy, it was mounted on underground counter-balances.
Several of the trapdoors were inadvertently discovered during the war; one of them in a wood near Great Leighs, Essex, by a courting couple. They suddenly felt the ground begin to move beneath them. When they found out why, in some alarm they notified the police who in turn notified the Army, and that hideout was no longer used.
Certainly everything possible was done to keep the hideouts inconspicuous. Most were sited in woods, often where the under-growth looked so dense that even animals could not get through it. Frequently the trapdoors of the hideouts were at the edges of footpaths, so that as long as the men who used them were careful, they could remove and replace the trapdoors without ever actually stepping off the paths. To reach a hideout in a cave in Scotland, on the Bowes-Lyons estates in Berwickshire, the Resistance men had to scale a sheer cliff overhanging a river, then leap into the cave through a waterfall. Officers from Coleshill who visited this hideout were given a sumptuous dinner of fresh salmon poached from a stretch of a river where the fishing rights were owned by the King's brother-in-law.
At Manston, not far from Margate, an Auxiliary Units Patrol decided to put its hideout in a man-made cave, believed to have been scooped out of the chalk in the seventeenth century by members of a religious order. To make sure that this hideout would not be discovered by the Germans, the Welsh tunnellers who made it went to the trouble of excavating an entirely new branch off one of the old passages. They concealed the room with a huge block of chalk that they mounted on rollers.
The Auxiliary Units hideouts were a major preoccupation of the men, and one by one they solved all the problems of building and maintaining the shelters. Paints were found that would resist condensation, and efficient ventilating systems, often terminating above ground in tree stumps, were devised. When several senior officers from Coleshill went to the Lincolnshire fens to inspect Patrols there they were invited to stay for dinner in one of the hideouts. The officers expected a makeshift meal, probably served on packing cases full of stores, but when they slipped down through the trapdoor they were faced with a long dining table covered with a crisp damask cloth. The candles were in candelabra, and the cutlery on the table gleamed.
At the end of the war Royal Engineer demolition teams were sent around the country to destroy the OBs to keep them from becoming the hideouts of criminals on the run of play places where small children might easily get hurt. However, a number of the hideouts were not destroyed and, although most of them have by now caved in, leaving only rain-washed dents in the ground to mark their positions, a few still survive, mostly on private land where they are unlikely to become a nuisance. Before it is too late ought not at least one of these be turned into a form of national monument or museum? Historically the operational bases of the British Resistance are at least as interesting as the Martello towers that line parts of the coast.