When I first arrived at the top secret Porton Down laboratory, I was aware of very little about its activities. I knew it was the UK’s chemical defence research centre and that over the years it had conducted tests with chemical agents on humans.
But what really happened there was shrouded in mystery. This made it a place which was by turns fascinating and scary. Its association with the cold war, reinforced by images of gas mask-wearing soldiers and reports of dangerous (and in one case fatal) experiments, also made it seem a little sinister.
The shroud of secrecy resulted in it being the subject of some lively fiction, such as The Satan Bug by Alistair MacLean, which revolves around the theft of two deadly germ warfare agents from a secret research facility and in the “Hounds of Baskerville” episode of the BBC drama Sherlock in which the hero uncovers a sinister plot involving animals experiments.
Even Porton’s own publicity material recognises that where secrecy exists imagination can take flight, and attests:
No aliens, either alive or dead have ever been taken to Porton Down or any other Dstl [Defence Science and Technology Laboratory] site.
But it’s also the place where in recent years scientists analysed samples confirming that a Novichok nerve agent had been used to poison former Russian spy Sergei Skripal and his daughter (coincidentally, just a few miles away). And where an active research programme on Ebola played an important role in the UK’s support to Sierra Leone during the 2014 outbreak.
So what is the truth? Over three years my research took me into the heart of the mystery, as I studied its extensive historical archive. The reality was not as I expected. I came across no aliens, but I did discover records of experiments that ran from the ordinary, through to the bizarre. And sadly, in one isolated case, the lethal.
Arriving at Porton Down, for example, was unexpectedly low key. The main gate is located off a public road on an otherwise quiet stretch between Porton Down village and the A30. It is in many ways visually similar to the entrance to Lancaster University in the north of England where I work as a lecturer in epidemiology.
Bar some signs announcing it as the Defence Science and Technology Laboratory (dstl) of the Ministry of Defence, the road is devoid of obvious security. No barriers block entry. This sense of the extraordinary hiding behind the ordinary was reinforced by the undistinguished visitor car park from where it is a short walk to the nondescript single story reception building.
There is also (perhaps unusually for a government chemical weapons research centre) a bus stop next to the main gate, from where you can get the number 66 to Salisbury.
Sgt Gordon Heard in the latest clothing for protection against toxic gasses and using a Risdual Vapour Detector in Porton Down in 1969.
Keystone Press / Alamy Stock Photo
So on my first visit in 2002 I made that short walk from the visitor car park to the reception and announced myself. I was pleased to find I was expected and looked into the security camera as bidden. After a hard stare from the receptionist I was issued, on that my first day, with a temporary pass. On it was written: “MUST BE ACCOMPANIED AT ALL TIMES” in bright red.
My contact, Dawn, arrived and led me through the main gate where security started to become more obvious. An armed policeman gave us a small nod as we passed through, his hands staying firmly on the machine gun strapped to his chest. Dawn paid little attention other than a brief hello and we were inside, heading to the headquarters.
It was from here that the management of Porton Down organised the programmes of testing which had ultimately resulted in my presence there – to research the health effects of chemical experiments on humans.
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Since its inception in 1916 it has researched chemical weapons, protective measures against chemical weapons, and has recruited over 20,000 volunteers to participate in tests in its research programmes.
Hut 42 – opening the archive
This archive was opened to my colleagues and I after previously being firmly hidden from public view. This shift in approach was the result of government approval for a study into the long-term health of the human volunteers. The action was triggered by complaints from a group of people who had been tested on and who claimed their health had been damaged as a result.
The government was also keen to ward off accusations of cover ups. In 1953 Ronald Maddison, a young RAF volunteer, died in a nerve agent experiment at the site. The original inquest was held in secret and returned a verdict of misadventure. But in 2004 the government ordered a second, public, inquest.
This, along with a police investigation into the behaviour of some of the Porton Down scientists persuaded the government to fund independent research into the health effect of the experiments.
A research group from the department of public health at the University of Oxford won IS WON RIGHT WORD? sk I was part of that group. Porton participated fully and opened its doors and archive to the project. I went ahead of the research team to deal with the practicalities of gaining access. My first task was to set up an office. So Dawn led me onwards to the building that had been put aside for our use.
We passed into the inner, more secure, area. This part of Porton Down was where the main scientific work was carried out. This inner secure area was surrounded by a high chain link fence and there was one principal entry point, next to a guard room.
Inspecting our passes was another armed MoD police officer. Alerted by my red pass he was all for barring my way until Dawn stepped in. Now vouched for, we were waved through and passed onwards to the building that would become my home for the best part of three years – hut 42.
‘People had neat handwriting then’
Hut 42 was a nondescript redbrick, single-story building, which sits next to the main library and information centre and from the outside could be mistaken for a school boiler room. In it were five desks and several metal filing cabinets closed with combination locks.
Our purpose there was to study the historical archive, including the handwritten books of experiment data. We then transferred that material into a database for later analysis. This process took four people two years of hard work, but we were lucky.
Porton Down’s record keeping was excellent. Early on I had worried that handwritten records would be hard to decipher and had asked a Porton Down librarian whether they would be legible. “Definitely”, was the reply. “People had neat handwriting then. It’s the records from the 1970s you’ll have to watch. They’re dreadfully scrappy,” he said.
And so it was proved. The records of tests from an era before computers, carried out with substances such as mustard gas, were routinely neatly and clearly documented.
Porton Down experiment book, showing drop tests to the arms during one of the first nerve agent tests.
A picture of a page in one of the experiment books on which is recorded the first nerve agent test for Tabun on April 10, 1945.
Thomas Keegan
I met Porton Down’s resident medical doctor in the archive to start discussing the nature of the experiments. Simon (not his real name) was in his mid-thirties with boyish curly hair and an anorak. “You’ll find everything you’ll need in here, in these cupboards,” he said. “First, I’ll show you how to open the cupboard. It’s like this”, he said. “A five number combination. Five times anticlockwise to reach the first number, four times clockwise for the second, three times anticlockwise for the third and so on.”
There was a pause while he demonstrated. “Sometimes they can be a bit sticky”, he said after the first attempt. He got the cupboard open on the second try.
The archive was a mixture of handwritten experimental and administrative records. The administrative records were essentially lists of attendees with dates and personal characteristics such as age. The experimental records reported the results of the tests with people in a variety of ways. Some were in the form of descriptive text, others used pictograms to record the site visually, for example where a drop of mustard gas was placed on the skin. Many contained tables of data, all hand drawn and as legible as if they had been printed. Our cupboards contained around 140 such books spanning a period from the start of the second world war to the end of the 1980s.
The story the records told was a fascinating one.
In the 50 years following the outbreak of the second world war, Porton Down encouraged over 20,000 men, nearly all members of the UK armed forces, to take part in experiments at the site.
These men (the regular armed forces had yet to admit women) took part in a programme of tests that ran from experiments using liquid mustard “gas” dropped onto bare skin to inhalation of nerve agents. There were also tests with antidotes and other gasses and liquids too.
Chemical experiments
The records show that between 1939 and 1989, over 400 different substances were tested at Porton. Mustard gas, sarin, and nitrogen mustard were frequently tested. These chemicals are known as “vesicants” for their ability to cause fluid filled blisters (or vesicles) on the skin or any other site of contact. First world war soldiers were familiar with the horrors of this gas, which was first used by Germany at the Battle of Ypres in 1915. John Singer Sergeant’s powerful painting Gassed expressed the effect of mustard gas on soldiers exposed in the trenches.
Other major chemical tests were riot control agents, such as CS and CR, these being the only chemicals tested that have been used by UK forces in peacetime, their purpose being crowd control.
Mostly, we were kept far away from anything other than paper records. As Britain had given up its chemical arsenal and any offensive capability in the 1950s, there was, as Simon had explained, no stores of chemical agents at Porton Down, except of course, small amounts of those that were needed to test human defences. By a circuitous route however, I came nearer to some than I was expecting.
‘Would you like a sniff?’
Hut 42, was not, it turned out, wholly for our use. While some Porton staff shared access to the archive and popped in now and then to examine records and take photocopies, the building had one other permanent resident – Porton Down’s in-house historian Gradon Carter. Carter was in his late 70s and had worked at Porton Down as an archivist for more than 20 years. He prided himself on knowing more than anyone alive about the history and administration of the institution.
He wore tweed and had the air of a world weary Latin master, but rather than the accoutrements of his trade being Latin textbooks, his were the paraphernalia of chemical warfare. Around his desk were examples of gas masks from various periods of history, and on the wall, posters inviting people to “always carry your gas mask”.
Gas attack: British information poster from the 1940s.
Shawshots / Alamy Stock Photo
One of his exhibits was a box, about the size of a packet of breakfast cereal, which contained glass phials, each carefully labelled with the contents. These included mustard gas, lewsite and phosgene.
The box was from the 1940s. It was a training tool to help troops recognise different gasses on the battlefield. “Would you like a sniff of mustard?”, he offered. It so happened I did. Nearly 60 years after it was first bottled, I can report that Carter’s mustard gas had very little smell, but I was reluctant to get close to test any of its other properties. He re-corked it. “Some lewisite?” he suggested.
Lewisite was produced in 1918 for use in the first world war but its production was too late for it to be used. Another vesicant, it causes blistering of the skin and mucous membranes (eyes, nose, throat) on contact.
I declined Carter’s kind offer.
Other chemicals appeared in the records less frequently. There were the lovely vomiting agents, which are designed to winkle their way under your gas mask to make you sick, which will make you take off your gas mask making you vulnerable to the next wave of attack by, for example, nerve agents.
These agents were relatively standard members of a chemical arsenal. In an effort to expand its horizons, Porton Down opened its collective mind in the early 1960s to the usefulness of psychedelics in warfare and tested LSD for its potential as a disruptor of enemy military discipline.
The tests showed that troops became unable to put up much of a fight, but ultimately the chemicals were rejected as means of mass disruption. You can see a video of a test at Porton Down with LSD below.
In the video, a troop of Royal Marines can be seen taking part in an exercise during which they are given LSD. Not long afterwards the men become barely capable of military action and seem to find almost everything funny. One man seems not to know which end of a bazooka to point at the enemy.
The most commonly tested substances at Porton, according to our data, were mustard gas, lewisite and pyridostigmine (more of which later) with thousands of tests undertaken. Less frequently tested were a basket of chemicals including sodium amytal (a barbiturate) and more strangely perhaps, 49 tests with pastinacea sativa – the irritant wild parsnip.
Not all men who took part in tests did so with chemical agents. Many visited Porton Down and were “tested” with substances that were not intended to be harmful but which must have been providing useful information of some kind. Some people were tested with “lubricating oil” (498 people) and “ethanol” (204 people). Many tests were with protective equipment such as materials for protective suits and with respirators.
Nerve agent tests
Around 3,000 people were tested with nerve agents. The number of nerve agents tested was not extensive, with six principal agents recorded. These were tabun, (known as GA), soman (GD), sarin (GB), cyclo sarin (GF), and methylphosphonothioic acid (VX).
The period of nerve agent research ran from the early postwar period to the late 1980s, and coincided with the cold war, when military tension between the Nato countries and the USSR was high.
The archive was rich in information on these tests. The records included detail of the time and place of each test along with details of who took part, noting both staff and volunteer participants. Records on the early tests are especially revealing.
Chambers like this were used to carry out tests on nerve agents.
Thomas Keegan
For example, in 1945 nerve agents were not yet known to Porton Down scientists. They had come close to discovering nerve agents when they had worked on PF-3, a chemical of the same organophosphate type as the nerve agents, but they had not thought it sufficiently toxic.
However, these agents were well known to German scientists, and to the German military who weaponised them during the second world war. Despite fears to the contrary, gas was not used in the fighting, though Germany had clearly prepared for chemical warfare.
Nazi agents and gin and tonic
Advancing US forces moving through Germany came across stockpiles of artillery shells in a railway marshalling yard near Osnabrück that contained suspicious liquids. The markings on the shells – a white ring on one type and green and yellow rings on the other – were new to the Americans. The shells were sent to the US and Porton Down for investigation.
After initial analysis, Porton scientists found that the shells with the white ring contained tear gas. The other contained an unknown substance (later it would be named tabun).
Tabun is one of the extremely toxic organophosphate nerve agents. It has a fruity odour reminiscent of bitter almonds. Exposure can cause death in minutes. Between 1 and 10 mL of tabun on the skin can be fatal.
On April 10 1945, after some laboratory tests, the scientists decided to test the new chemical on people. In fact, as Carter pointed out to me, disaster could have struck immediately as the first nerve agent to arrive at Porton for testing was transported to the lab in a test tube stoppered only with cotton wool.
Thinking this was a new variety of mustard gas, they placed drops on the participants’ skin. The scientists also placed drops in the eyes of some rabbits. The records show that before any serious effect to the humans could be noted one of the rabbits died, giving the scientists running the tests a fright.
The chemical was quickly wiped off the men’s arms and the test ended there. According to a brief memoir supplied by Carter, Dr Ainsworth (who was involved in the tests) said that Captain Fairly (the Porton scientist being tested on) had been shaken by the experience but recovered “after a stiff gin and tonic in his office”.
This sporting attitude to self-testing was not uncommon among scientists, however. Dr Ainsworth later tested a method for reducing the effect of a splash of nerve agent on the skin which involved a tourniquet and opening a vein – something he thought worked well.
But he was used to the pioneering methods of the day. “Taste this,” the pharmacologist John (later Sir John) Gaddum had ordered on one previous occasion. Dr Ainsworth sipped the liquid offered and reported that it tasted a little like gin. “That’s strange”, Professor Gaddum said. “I can’t taste anything. It’s diluted lewisite and the rats simply won’t drink it.”
Back at the wartime testing lab they were keen to find out more about what was now understood to be a new type of chemical agent developed by German scientists and weaponsied by their armed forces. The following week, ten people were exposed in a chamber, at the higher concentration of 1 in 5 million. In the pioneering spirit not uncommon at Porton, four of the subjects: Commandant Notley, Major Sadd, Mr Wheeler and Major Curten were Porton staff. Major Curten reported having a tightness of chest, and a slight contraction of the pupils, unlike the commandant who had no reaction but thought the gas smelled of boiled sweets.
An undated photograph of the southern end of the Porton Down campus showing the bus stop outside. The grey building is thought to be one of the exposure chambers.
Thomas Keegan
Later that morning the scientists had another go, this time at a higher concentration, 1 in 1 million. The symptoms were now more noticeable, with more than one person vomiting and others needing treatment the following day for the persistent symptoms of headaches and eye pain.
Given what we have since learned about tabun, it seems at the very least cavalier of the scientists to conduct these tests on themselves and others. They were were lucky not to have been seriously injured or even killed, but those were the risks they seemed willing to take.
Fatal consequences
The last entries in the archive for nerve agent tests were for 1989 so newer compounds such as novichok, used in an attempted assassination in nearby Salisbury, were not included. One later nerve agent tested in the 1960s was VX, then a scarily potent new nerve agent.
According to the Centers for Disease Control in the US, VX is one of the most toxic of the known chemical warfare agents. It is tasteless and odourless and exposure can cause death in minutes. As little as one drop of VX on the skin can be fatal.
It was not developed into a weapon by the UK, as by then it had abandoned an offensive capability, but tests were carried out on a relatively small number of volunteers. I mentioned VX to Carter. He recalled that the first sample of VX was first discovered, accidentally, at an ICI chemical factory in the UK and sent to Porton in the regular post. Luckily, nobody was exposed.
In one notorious episode however, the tests of nerve agents on humans did not go as expected.
Ronald Maddison, 20, died after being exposed to a nerve agent at Porton Down.
PA Images/Alamy Stock Photo
As I referred to earlier, in 1953, during an early nerve agent experiment, the young airman, Ronald Maddison died. Testing was paused at Porton after an inquiry by the eminent Cambridge academic Lord Adrian and limits on exposures were set after resumption in 1954. A second inquest into the death returned a verdict of unlawful killing in 2004.
While no charges were made against the scientists involved, the Ministry of Defence agreed to pay Maddison’s family £100,000 in compensation.
One of the founders of the Porton Down Veterans Group, Ken Earl was in the same experiment. He remembered vividly being in the same chamber as Maddison, and while not affected seriously at the time, felt his health issues later in life were directly related to the test. In an interview with the BBC, he attributed the many health problems he suffered through his life, including skin conditions, depression and a heart irregularity, to his experience at Porton Down.
Our research could not establish a direct link to the kind of ill health Earl suffered. But our data on the short-term effects did show a good deal about the immediate aftermath of a nerve agent exposure, similar to the type Earl experienced.
The physiological effect of exposure to nerve agents varies greatly between individuals as our previous research has shown. The strength of symptoms varies too. Five of the six participants in the same test as Maddison did not report adverse effects other than feeling a bit cold.
However, tests before this had shown that certain effects were consistently seen with nerve agent exposures. In July 1951 six people participated in a test with soman. The lab book notes:
5/5 experienced pain in eyes, blinker effect and blurred vision 30 minutes after exposure (these symptoms continued for 24 hours). 1 participant vomited 4 hours after exposure. 2 participants vomited 24 hours after exposure. Eye pain and vision improved after 48 hours but not normal – return to normal after 5 days. 4/5 given multiple doses of atropine.
While these effects must have been unpleasant, it is also shown that participants in nerve agent tests had between one and two “exposures”. Those in tests with other chemicals such as mustard gas may have had many.
To further regulate exposures, strict limits on the amount of nerve agent allowed in tests were imposed after Maddison died. The levels of exposure typically experienced by servicemen induced: pinpoint pupils (miosis), headaches, a tightness in the chest and vomiting. These symptoms recur many times in the records, as does documentation of the drugs used to treat them, typically atropine and pralidoxime.
A new era
Despite the range of agents which have been developed, chemical weapons have rarely been used by states in conflict, perhaps held back by adherence to the Chemical Weapons Convention or by their difficulty of use.
Despite this they were used by Iraq (not then bound by the CWC) in the Iran-Iraq war (1980-88), who used mustard gas and tabun against Iranian troops. They have also been used by states against civilians – for example by Iraq against its Kurdish population and more than once by Syria against its civilian population between 2014 and 2020.
In 2017, North Korean agents used VX to assassinate Kim Jong-nam, North Korean leader Kim Jong-un’s half-brother in Kuala Lumpur, Malaysia. And more recently the Russian opposition leader Alexei Navalny was poisoned with a nerve agent. He later recovered only to die in a Russian prison in early 2024.
These are not just remote threats. As I previously noted, a particularly high-profile example of a state using a chemical weapon to kill someone took place in the UK in 2018 when it is alleged that the Russian state tried to kill an ex-KGB spy using small quantities of the then new and especially toxic nerve agent Novichok.
Sergei Skripal, the intended victim, and his daughter Yulia survived the attack.
A public inquiry heard how the Skripals were found slumped in a park in Salisbury. While the presence of nerve agents was not at first suspected, the emergency services noted how the Skripals suffered from a range of symptoms including pinprick pupils, muscle spasms and vomiting. For those experienced with nerve agents these symptoms are typical.
But these symptoms were not known to Nick Bailey, a detective sergeant who had been assigned to check over a house in Salisbury, home to the two people that had recently been found collapsed. This should have been routine but the first indication to DS Bailey that something was amiss was when he looked in the mirror.
His pupils, normally wide open at this time of night, had shrunk into pinpricks. He was also beginning to feel very strange. But it was when Bailey’s vision fractured and he vomited that he knew something was seriously wrong.
It would later become clear that the agents sent to kill Skripal had sprayed the liquid nerve agent onto the door handle of the Skripal house. Sergei and his daughter both used the handle and were poisoned. So was Bailey, who had closed the door and locked it after his checks on the house later that evening.
Four months later, the boyfriend of Dawn Sturgess found a discarded perfume bottle in nearby Amesbury, picked it up and then later gave it to her as a present. Neither could have imagined it had been used to bring Novichok to Salisbury and left behind by the attackers. Sturgess died after spraying the contents onto her skin. Her boyfriend survived.
It was in partnership with experts at Porton Down that the local health services were able to treat the victims. According to the inquiry, a key challenge was for the hospital to work out what had poisoned the Skripals so they could treat them effectively. Porton Down worked nonstop to determine what type of nerve agent had been used. Once the cause was known the hospital was able to save the Skripals’ lives.
That Porton Down is situated just a few miles from Salisbury where the Novichok attack took place was probably useful to those treating victims. The Russian state however, used this proximity to try to muddy the waters of accountability for the poisoning, but there seems little doubt that blame for the nerve agent poisoning lies with Russia.
Despite the efforts of those agents, five out six people poisoned with Novichok survived, not unscathed perhaps, but alive. That they did so is in some way the result of the expertise and knowledge gained over years of nerve agent research at Porton Down.
It seems clear that the more information about the effects of nerve agent exposure that are known outside specialist research circles the better. Though nerve agent attack is extremely rare the events in Salisbury and Amesbury have shown they are not impossible.
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