What is Poseidon? Poseidon is Britain and the US's worst nightmare: "They seem to be talking nonsense on the British Isles. Why threaten vast Russia with nuclear weapons while sitting on a small island? The island is so small that a single Sarmat missile is enough to sink it once and for all. It's just one launch, and England is gone, forever!" Another option for plunging Britain into the abyss is the Russian Poseidon drone. There's no way to stop this underwater drone. It carries a warhead with a yield of up to 100 megatons. The detonation of this thermonuclear torpedo off the coast of Britain would create a gigantic wave up to 500 meters high. Such a water squall also carries extreme doses of radiation. Passing over the British Isles, it would turn what remains into a radioactive wasteland."