Researching Britain's Secret Defences


13 September 2022
Subtitled ‘Civilian Saboteurs, Spies and Assassins during the Second World War’ historian Andrew Chatterton's new book, 'Britain's Secret Defences' looks at the the selfless and extraordinarily daring roles that some of our family members would have stepped up to play should the Nazis have invaded Britain during the Second World War.

Guerrilla fighters, assassins, saboteurs, spies and honey traps – Britain’s secret Second World War civilians resistance

Researching your family’s history during the Second World War can be a challenging task, often full of confusing acronyms and little detail. For those with relatives in reserved occupations or too young or too old to join the regular forces research often focuses on groups such as the Home Guard, Air Raid Precautions or the fire service. However, over the past few years, new information on highly secret civilian groups has begun to emerge – having signed the Official Secrets Act, a majority of these people went to the grave without telling a soul, not even their closest family and friends. 

Their roles were twofold. One group represented a suicidal effort from highly trained, highly motivated civilians to hold up any German invasion of the country. If the worst happened and Britain was defeated militarily another group would act as a resistance force against the occupying Germans. These were not the civilians we have in our mind when we think about Britain’s civilian defences during the Second World War. This was not Dad’s Army but some of the most remarkable men, women and teenagers whose relatives very rarely know just what their true role was during the war.

Auxiliary Units

One group was called the Auxiliary Units. Made up of men in reserved occupations such as farmers, farm workers, estate workers, gamekeepers, miners etc, their role was to disappear to secret underground bunkers (hidden the length of the country) and in Patrols of 6-8 men, come out at night and cause as much chaos as possible to disrupt the invading army’s supply chain. They were very well equipped with the latest weapons and explosives and only had a life expectancy of two weeks, once the Germans had arrived in their area. Most used the Home Guard as a cover and signed the Official Secrets Act, meaning that many relatives have no idea what their family member was actually up to during the war. We believe that there were around 6,500 during the course of the war.

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Special Duties Branch

Another of these highly secret groups was the Special Duties Branch. This was made up of the elderly, mothers, doctors, vicars, teenagers - anyone who could stand on the street without attracting the attention of the invading army. They were to take down notes on the Germans passing through (insignia, regiment, weapons, numbers, vehicles, direction of travel), and pass these notes on via dead-letter drops and runners. The last runner in the line passed the note onto a civilian wireless operator who then passed the info onto ATS women in bunkers like those inhabited by the members of the Auxiliary Units. This info was then passed on to the local command or GHQ. Again, these civilians all signed the Official Secrets Act and we believe that there were around 4,000 countrywide.

Section VII

The final group was run by SIS (MI6) and called Section VII. Whilst the Auxiliary Units and SDB were anti-invasion groups, Section VII civilian cells were to only become active after the Germans had defeated Britain militarily and occupied the country. These ‘cells’ were often made up of family members, women and teenagers as young as 13 or 14. Their role was to make life as difficult as possible for the occupying forces by destroying infrastructure and railways, assassinating German officials and British collaborators and collecting information on the occupying forces and passing it on via wireless sets to an unoccupied bit of the country or even a British government in Exile. There is increasing evidence that pre-prepared escape lines for fugitives of the occupation were also set up. Again, these groups all signed the OSA and most died without saying a word.

Research & clues

Of course, the very nature of these groups means that there was very little left behind in terms of paperwork or items. The Auxiliary Units were the only group to receive any kind of recognition, a small lapel badge (often the first clue that a relative was involved when found amongst belongings). The Special Duties Branch and Section VII received no public recognition at all.

The lapel badge of the Auxiliary Units. Image courtesy Andrew Chatterton.

There is occasionally some paperwork (usually stand-down letters issued in July 1944 for the SDB and November 1944 for the Auxiliary Units, no such letters exist for Section VII as far as we know).

Resources such as the 1939 register can be useful to confirm addresses (and therefore proximity to bunkers sites) but this is only the case in England and Wales. In Scotland, researchers have to rely on family stories and information.

Organisations such as the Coleshill Auxiliary Research Team (CART – are also a fantastic resource. The website lists all the known members of the Auxiliary Units and Special Duties Branch and can be searched by surname or county. It also has a huge amount of information on the secret bunkers, weapons, training and background of these remarkable groups.

Much of the information comes from family members who remember stories being told by relatives. The term ‘Special Home Guard’ often comes up as do stories of handling explosives and silent weapons. Too often these stories are dismissed by relatives who unfortunately regret not asking more questions when their relative has passed on.

Finally, my new book, Britain’s Secret Defences (Casemate Publishing, £19.95, hardback) has been recently published that covers all of these groups and more. It also includes more on what to look out for if you suspect your relative might have been involved in such groups.

Did your ancestor serve in one of these secret organisations?

We would be very interested to hear if so. Please email [email protected] and we will get back to you to request further details.