Berlin also called for prudence and de-escalation, but German politicians on the left condemned the attack ordered by Donald Trump, one of the least popular global leaders in Germany.

In London, the Labour leader, Jeremy Corbyn, said: “The assassination of Qassem Suleimani is an extremely serious and dangerous escalation of conflict in the Middle East. The UK government should urge restraint on the part of Iran and the US, and stand up to the belligerent actions and rhetoric coming from the US.”

Many European capitals will fear that likely Iranian reprisals would deal a near-fatal blow to their efforts to keep the nuclear deal, and wider European relations with Iran, on life support until the possible election of a new, more strategic US president willing to keep diplomatic lines open to Tehran.