Owen Bowcott and Rob Evans
The government was known to have produced 5m anthrax-filled cakes to infect cattle in Germany during the war, but the latest documents show research was carried out into a far larger variety of diseases, mostly in Porton Down, near Salisbury, and Pirbright in Surrey.
Experts reported to the War Cabinet's Porton experiments sub-committee, which acknowledged that "bacteriological warfare" was outlawed by the 1925 Geneva protocol. The minutes, only now released, are labelled "secret" and "to be kept under lock and key". One session on "Toxin X" – thought to be botulinum – was so sensitive the minute records: "Not circulated."
An interim report in January 1941 said: "The diseases considered most likely to be effective in bacteriological warfare are:
• Human diseases: enteric group (typhoid and para-typhoid), dysentery and cholera.
• Animal diseases: anthrax, foot-and-mouth disease, rinderpest, glanders, and swine fever. (Anthrax and glanders also affect human beings under conditions favourable for infection)."
Biological warfare was not thought
The study queried whether retaliation should be limited only to diseases or infections "first used" by the Nazis. "... It is assumed that retaliation would be made simultaneously and on a maximum scale with all the means at our disposal".
Human diseases, it was said, could be introduced into "enemy territory only by saboteurs" – for example at "restaurant food counters". That would make it "very difficult to achieve on a scale sufficient to produce serious effects".
Attempts to infect reservoirs from the air would
By February 1941 work had been carried out to fit "streamlined steel containers" to the bomb bays of Wellington and Blenheim bombers.
Estimates of the time needed to prepare "retaliatory measures" in each disease were set out. Only small quantities of typhoid, dysentery and cholera would be required, it advised, and experiments were being made into "methods for use".
Infective anthrax spores could be produced in large numbers at a few days' notice, three strains of foot-and-mouth virus were available but a three-week "reactivation" period was needed. Supplies of rinderpest – or cattle plague – had to be obtained from Africa and a new isolation station built. Large batches of glanders – a bacterial infection – could be made up in two weeks. Experiments were being conducted on swine fever.
The sub-committee recommended that research into human and animal diseases continue. Scientists at Pirbright found their cows were unco-operative with attempts to poison them with cattle feed cakes containing infections or ground glass dropped from the air.
By November 1941 anthrax-filled cakes were emerging as the favoured, practical means for "taking offensive action".
The committee justified the research on the basis of defensive necessity.
Dr Brian Balmer, of University College London, who is the author of Britain and Biological Warfare: Expert Advice and Science Policy 1930-65, said the newly released material provided fresh insights into the UK's wartime biological programme. "We have not seen such a detailed list before." He added: "The process [at Porton Down] most likely involved starting with a list of likely sources for infections and then finding that some are difficult to aerosolise or are unstable or are otherwise unsuitable for weaponisation."
Neither side used biological weapons in the war.