A government report covered by the Guardian in 2002 indicates that between 1940 and 1979, the Ministry of Defence "turned large parts of the country into a giant laboratory to conduct a series of secret germ warfare tests on the public" and many of these tests "involved releasing potentially dangerous chemicals and micro-organisms over vast swaths of the population without the public being told." The Ministry of Defence claims that these trials were to simulate germ warfare and that the tests were harmless. Still, families who have been in the area of many of the tests are experiencing children with birth defects and physical and mental handicaps and many are asking for a public inquiry. According to the report these tests affected estimated millions of people including one period between 1961 and 1968 where "more than a million people along the south coast of England, from Torquay to the New Forest, were exposed to bacteria including e.coli and bacillus globigii, which mimics anthrax." Two scientists commissioned by the Ministry of Defence stated that these trials posed no risk to the public. This was confirmed by Sue Ellison, a representative of Porton Down who said that the results from these trials "will save lives, should the country or our forces face an attack by chemical and biological weapons." Asked whether such tests are still being carried out, she said: "It is not our policy to discuss ongoing research." It is unknown whether or not the harmlessness of the trials was known at the time of their occurrence.

Answer this question, if possible (if impossible, reply "unanswerable"): What was the purpose of Porton Down releasing germs on the public unknowingly?
unanswerable