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UK Public Area Biological Warfare Experiments 1949-1975

Although many of you may be aware that the UK Chemical and Biological warfare research centre, Porton Down, have in the past few years admitted to conducting some of their biological warfare (BW) experiments in public areas of the UK, the full extent of this type of research may come as a surprise.

To discover what prompted Porton Down to turn the UK into a giant laboratory for their experiments (trials) we have to go back to 1949 and examine what exactly it was that Porton Down scientists were doing in the Meadow Road area of Salisbury, the nearest city to their research centre.

The Salisbury Trials 1949-1953

Porton’s explanation of the purpose of the 1949-1953 Salisbury experiments varies according to it’s prospective audience. Residents and City authorities were told:

“The municipal authorities, with the knowledge of the Home Office, willingly gave permission for the trials to take place and their co-operation together with that of the Police and residents of the area was wholeheartedly given.”

This “wholehearted co-operation” stemmed from the fact that Porton gave the following reason for the experiments:

“The inhabitants of the area were told that the trials were to study smoke pollution of the air. They were most co-operative, and when requested, permission was readily given for sampling equipment to be put on private property- though in general sampling points were arranged to be put in the streets or in alley-ways leading to the back garden entrances.”

“Air pollution studies“, along with “atmospheric meteorological investigations” are two of the main cover stories promoted by Porton Down in the past whenever they wished to conduct clandestine research in public areas. As official Porton historian G B Carter stated when discussing later Porton public area trials:

“As in the FP trials, a cover story about meteorological and air pollution work was readily constructed for any inquisitive inquirer. Both aspects were of course not incorrect.”

aerial photo

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The real purpose of these trials can be found on page one of the Porton scientific report that detailed the trials results.

“The discovery of agents of considerably greater effectiveness has brought to the fore once again the requirement for knowledge concerning the travel of gas in a built-up area.

There has been a shift of view-point too in that no longer are we interested in the concentration of gas in the immediate neighbourhood of the bomb burst but we are interested in the general coverage of area experiencing particular dosages for given quantities of bomb-charging. Such data would be of direct use in the estimation of weapon expenditure in a gas attack on a town.”

So there we have it, Porton Down scientists carried out the Salisbury trials in order to investigate how much of the newly discovered nerve agents would be needed in order to gas an entire town or city. Instead of pinpointed gas attacks on military targets, scientists were now investigating the possibilities of gassing of entire cities. This is reinforced by evidence presented to the US National Academy of Science in the mid 1990s. The evidence was presented by the US Army as a historic background of the US biological warfare programme. It shows that the Salisbury trials were the first of three methods that were used to investigate the problems of estimating munitions expenditure for a BW counter-city attack.

“Three approaches to the problem of estimating munitions requirements for the strategic use of BW agents against target cities were available.

The first, which was investigated by the British, used wind-tunnel studies on city models and a small number of field tests within a city itself (Aanensen 1951). Important results were obtained…..”

These trials ran from December 1949-1953, during which time Porton scientists examined many aspects of attacking a city with CBW agents. With the assistance of the Wiltshire County Fire Brigade, temperature differences at 100 ft were measured mounting monitoring equipment on their 100ft turntable ladder.

The trials procedure was relatively simple- scientists operated smoke generators (chemical flares) as a single point source and this smoke (which was used to simulate nerve agents) was carried on the wind across the Meadow Road- Gas Lane area. Air monitoring devices were set up downwind of the source which took samples over a period of time. The results from this sampling were analysed and synoptic charts (see below) were produced which showed the various concentrations of the smoke across the affected area. The nerve agent simulant used in these trials was salicyladazine- a fluorescent smoke. Porton scientists considered that it had a smell similar to that of curry, whereas local residents thought it to be more like the aroma of gravy!

synoptic chart that was produced from the sampling results of the first trial

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The above figure shows the synoptic chart that was produced from the sampling results of the first trial, which was held on 19 December 1949. Comparison with the aerial photograph shows the location of the smoke generators (marked in yellow in the aerial photo).

It is interesting to note that during some of the first series of the Salisbury trials, air sampling was conducted at a height of 20ft - bedroom height. The implication being that measurements were needed to estimate the dosage that would be received by any city residents who were asleep, this was indicative of planning for sudden surprise night time attack.

During December 1949 - April 1950, 10 trials were conducted. The trials were continued during 1952-1953 when 12 more trials were carried out, with some being conducted at night.

According to Porton historian G B Carter, C J M Aanensen, the scientist in charge of these trials then wrote a TOP SECRET memo in 1952 entitled “A note on the possibility of travel of BW and CW agents across the UK”. It would seem that the results from the Salisbury trials had indicated that a new method of conducting both chemical and biological warfare was possible. This new method would eventually make chemical and biological bombs, and the vast numbers of aircraft needed to drop them, redundant.

It was the dawn of a new era of public area experimentation.

In 1952, Porton’s Meteorological Section produced a Top Secret paper which concluded that conditions frequently occurred over the UK “in which an enemy releasing toxic agents in moderate quantity along an extended source, could cover areas in the order of thousands of square miles with effective dosages”. This report referred to field trials carried out in the US under the code name “Stanford Project”. In other words the Stanford Project had successfully conducted simulated attacks on large areas of the US using a “simulant” of a toxic agent.

At the time, 1952, no CW agent of a sufficiently toxic nature was available that could be used in such an attack. By 1953, attention at Porton had turned away from using CW agents in such an attack; instead, Porton’s focus turned to applying the new technique in the field of biological warfare. At the time, BW attacks were planned as being delivered by massive fleets of aircraft dropping BW cluster weapons (the RED ADMIRAL bomb) in counter city attacks. The new technique offered contamination of large amounts of enemy territory with a much smaller fleet of aircraft, and no need for expensive weapons development, production and storage programmes. Modified tanker aircraft could be fitted with stainless steel tanks and relatively simple aerosol spraying equipment could be fitted.

What was now needed was information on the movement of parcels of air close to the ground. To do this CDEE Porton Down embarked on the largest series of public area experiments ever conducted in the UK.

In order to conduct these new more widespread experiments CDEE Porton Down needed a tracer capable of tracking parcels of air. It was decided to use the same chemical compound as used in similar US BW experiments, Zinc Cadmium sulphide.

Zinc Cadmium sulphide is a finely ground compound (the particles were between 1-5 microns in size- the same size as a BW agent) and fluoresces a characteristic yellow colour when illuminated by ultra-violet light. The ZnCds trials procedure followed a similar pattern- a source sprayed large quantities of ZnCds particles which were carried by the wind across country. Various sampling stations were set up downwind of the source which tried to collect ZnCds particles present in the air. These samples were examined under ultra-violet light and the number of ZnCds particles were counted. Particle counting was a very labour intensive and subjective procedure which was open to error.

By 1957 CDEE Porton Down had become familiar with using ZnCds on a regular basis and the focus turned to testing the theory of Large Area Coverage. This theory proposed that a single source disseminating a BW agent along the coast of the UK could contaminate an area of 10,000 square miles. Over the next 4 years this theory was tested by ZnCds disseminations from aircraft and ships off the coast of the UK.

Porton ZnCds LAC Experiment 131 1 19 57


The long distance Travelof Particul (10)

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As can be seen in the trials map featured above, not all experiments went as planned. On the 18th August 1959 an aircraft flew a track off the coast of the UK from Cromer- Swanage spraying ZnCds as it travelled. For some reason south Dorset received an enormous dosage of the simulant. At the county town, Dorchester, a Porton air sampling team collected 4,315 particles of ZnCds- the true figure may have been higher as the scientific report records that the air sampling at Dorchester was stopped before the cloud had completely passed.

By the early 1960s the data from the LAC experiments had been analysed - the results horrified UK military chiefs. The experiments had proved that the UK could be successfully contaminated with BW agents by one or two aircraft flying off the coast. If a BW agent have been sprayed instead of simulants Government scientists estimated that up to 38,000,000 people could have been infected in a single attack.

In order to further investigate off target (LAC) BW attacks on a city it was decided to conduct ZnCds experiments on an English city. At least two of these “attacks” were made during August 1960 on the Wiltshire city of Salisbury. An aircraft flew a 100 mile arc 40 miles upwind of Salisbury spraying ZnCds at a rate of 1lb/mile. A network of rural and city air sampling stations were operated by CDEE Porton personnel in order to collect a representative sample of ZnCds particles present in the air. According to the relevant Porton Trials Programme-

“Source emissions may be made in late evening or very early in the morning depending on meteorological conditiond and on which aspect (night travel or morning fumigation) is of greatest interest.”

The results of these trials were inconclusive so in 1963 Porton decided to conduct a new series of trials in a different city, Norwich. The first ZnCds experiment carried out in 1963 is reported on in Porton Field Trial Report No 610. Porton has yet to publish trials results for the other 1963 Norwich experiments. This may be an example of the normal Porton procedure of not reporting on trials failures. It is known that other ZnCds experiments were planned for 1964- Porton Programme 2/64 shows in some detail how these trials were to be conducted. It also shows that the Norwich Police were very involved in assisting CDEE Porton in the conduct of the trials. Police officers acted as air sampling operators, nominated sampling sites and offered the use of the City Police HQ at City Hall as the main Control Point.

As with the earlier Salisbury ZnCds trials, the Norwich ZnCds experiment results proved to be inconclusive. As far as is known the planned 1964 Norwich trials were the last of the series of Porton Down ZnCds public area experiments. It was felt that the use of ZnCds in public area experiments had run it’s course.

Porton now turned to using live bacteria in public area experiments- for the next 12 years the south of England, Dorset in particular, would become Porton’s new outdoor laboratory.

Porton Down spray experiments on Norwich