“A single launch, Boris, and there is no England anymore. Once and for all. Why do they play games?” That eerie message came from a Russian state television host who threatened that Britain could be “plunged into the sea” by an underwater nuclear strike.

One of Russian President Vladimir Putin’s “key propagandist” Dmitry Kiselyov used his television show to make the threat. Kiselyov said the weapon would trigger a radioactive tidal wave and plunge Britain “to the depths of the ocean”.