The outgoing leader warned on Friday that Iran and the US must de-escalate tensions, otherwise the Middle East will see yet more conflict that would “bring further misery to the region, 17 years on from the disastrous invasion of Iraq.”

Corbyn branded the assassination of Soleimani, who was regarded as the second-most powerful person in Iran after Supreme leader Ayatollah Khamenei, as “an extremely serious and dangerous escalation of conflict.” He called on PM Boris Johnson’s administration to attempt to put the brakes on the military actions of the United States.

Earlier, British Foreign Secretary Dominic Raab said that the UK government “recognized the aggressive threat posed by the Iranian Quds force led by Qassem Soleimani,” but that any escalation of the conflict would be “in none of our interests.”

US Secretary of State Mike Pompeo took to social media to reveal that he and Raab had discussed the incident, and claimed Britain acknowledged the aggressive threats posed by the Iranian Quds Force. "The US remains committed to de-escalation," Pompeo added.

Soleimani was killed in a US military airstrike near Baghdad International Airport in the early hours of Friday. Ayatollah Khamenei -who warned that Iran would unleash “harsh revenge” on those responsible for the attack -has installed Brigadier General Esmail Ghaani as Soleimani’s replacement. Ghaani served as Soleimani’s second-in-command in the Quds Force.