Russian state television has visually shown that the UK will be wiped out by a nuclear tsunami if the war in Ukraine escalates.
Channel One anchor Dmitry Kiselyov said an underwater missile could spark a 500-metre radioactive wave that would wipe out the UK and Ireland.
In his Sunday evening primetime show, he told viewers that Russia's underwater Poseidon missile has the capability to spark a 500-metre radioactive tsunami that would wipe out the UK.
The Poseidon is an autonomous, nuclear-powered unmanned underwater missile approximately 20 metres long and weighing up to 100 metric tons.
"The explosion of this thermonuclear torpedo close to Britain's coastline will cause a giant tsunami wave, up to 500 metres high," Kiselyov said.
"This wave also carries extreme doses of radiation. Having passed over Britain, it will leave what is left of them in a radioactive desert, unfit for anything for a long time."
The threat comes as Britain's Prime Minister Boris Johnson is set to announce a new military aid package to Ukraine when he addresses Ukraine parliament on Tuesday.
Britain has already sent Ukraine equipment, including missiles and missile launchers. The new package includes electronic warfare equipment, a counter battery radar system, GPS jamming equipment and thousands of night vision devices.
In advance extracts of the address released by the prime minister’s office, Johnson evokes a 1940 speech by World War II leader Winston Churchill as the UK fought attack from Nazi Germany.
Johnson will say that “the British people showed such unity and resolve that we remember our time of greatest peril as our finest hour.
"This is Ukraine’s finest hour, an epic chapter in your national story that will be remembered and recounted for generations to come."
Ukrainian President Volydymyr Zelensky addressed Britain’s parliament on March 8, and also likened his country’s struggle to Britain’s fight against the Nazis. Johnson visited Kyiv on April 9.