'To develop and manufacture a devastating and demoralising weapon, deliverable by air, hitherto unknown by mankind.' In 1933 when Nazi Germany was on the rise, this was the brief issued to the secret K1 research facility, to manufacture a weapon so terrifying to foreign nations that it would deter the use of any specialist weapons against the UK. But what if that weapon was too terrifying? What if the exercises, planned for use on animals, were so...