Britain and the US already have 'Plans A, B and C' for how they would take out the entire North Korean leadership, the Mirror can reveal.
Elite forces are already being trained for a scenario in which they are ordered to eliminate Kim Jong-Un and his military advisers, former Navy SEAL Brandon Webb said.
The 43-year-old spent 13 years in the US Armed Forces and later took charge of the SEAL's Sniper School which trained Chris Kyle whose exploits the film American Sniper were based on.
"I think it would be very easy for the UK or the US to, if they wanted, swiftly take out the entire North Korean leadership," said Mr Webb.
"Very quickly, with a special operations unit.
"The intelligence capability and the special ops capability we have today is incredible.
"Most people have no idea really how effective the US and the UK are at conducting these missions."
The world is watching in fear as Trump brought the US to the brink of war with North Korea by threatening a nuclear attack.
Arms folded angrily, President Trump said: "North Korea best not make any more threats to the United States.
"They will be met with fire and fury like the world has never seen."
Within hours, North Korea's army said it was "carefully examining" a possible missile strike on the US Naval Base in Guam, a Pacific island.
A military spokesman accused the United States of devising a “preventive war”.
North Korea said any attempt would be met with an "all-out war wiping out all the strongholds of enemies, including the U.S. mainland."
Mr Webb, who is now retired and runs a media company for veterans, said the US would most likely model an assassination mission on the killing of Osama Bin Laden.
In 2011, a team of around 20 US Navy SEALs flew into Pakistan and took out the terror leader as he was holed up in a compound.
An image of then-President Obama and Secretary of State Hillary Clinton watching Operation Neptune Spear unfold from the White House became one of the most iconic of all time.
"There are probably already Plans A, B, C in place," said Mr Webb.
"For when the situation dictates, that’s part of what military and special ops community do.
"They constantly rehearse scenarios, to deal with modern day threats.
"It would come completely with the element of surprise, like how they orchestrated the OBL raid.
"They flew into Pakistan, completely undetected, and really didn’t ask permission until after the fact.
"I think it would be conducted in similar fashion.
"For the US it would be Delta Force - they would be the operational element.
"TF-160 helicopters doing a high altitude, high opening parachute op from 20,000-plus feet, from across the border of South Korea.
"And then fly that under canopy, undetected because radar can’t pick up the canopy.
"There’s all sorts of scenarios."
For all the inflammatory words, experts remain divided on just how dangerous the threat is posed by Kim Jong-Un and his regime.
And Mr Webb, whose book 'The Killing School' tells the story of US Navy SEALs in action, said he believes it unlikely that the US or her allies will take such drastic action any time soon.
"I don’t see it massively giving us an advantage," he said.
"It’s the resources that happen after regime change.
"You don’t want to leave a massive power vacuum.
"North Korea is very different culturally where they practically worship their leader.
"I see our strategy in North Korea as continuing to be very similar, a 'wait them out' strategy."
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