But with American and Israeli officials talking about a campaign that could last several more weeks, that does not look like an immediate prospect.

In the meantime, could allies be persuaded to send ships to escort merchant vessels through the vital waterway?

“Germany will not participate with its military in securing the Strait of Hormuz,” Pistorius said on Monday.

EU foreign policy chief Kaja Kallas later said there was a “clear wish” to extend EU naval operations in the Middle East, but that EU foreign ministers declined to extend an existing naval mission in the Red Sea. “This is not Europe’s war,” she added.

The EU’s Operation Aspides was launched in 2024 to help meet the threats to shipping posed by the Iranian-backed Houthi rebels in Yemen but, with a strength of just three warships, it is relatively modest.

Germany’s Foreign Minister, Johann Wadephul, said his government wanted to hear from Israel and the US “when they believe they will have achieved their military objectives in Iran” before discussing new security arrangements.

Of the major European allies, France’s President Emmanuel Macron is perhaps the keenest to get involved, saying a week ago that he was trying to put together a coalition to escort vessels and guarantee freedom of navigation.

But he said this could only happen once the “hottest phase” of the conflict was over and a few days later, his Defence Minister, Catherine Vautrin, said there were no immediate plans to send vessels into the Strait of Hormuz.

Sharpe said a potential escort operation would be much more complex than Operation Aspides, with threats coming from three directions: the air, surface and underwater.

“Unlike with the Houthis, where it was only an air threat, with Iran, you have all three and you want to try and shoot these things before they’re fired,” he said. “That’s not always possible.”

At the moment, Trump’s somewhat shellshocked allies are hesitating outside the door marked “Iran involvement”, looking nervously at each other but conscious that inaction is not really an option.

Sir Keir said the solution needed to involve “as many partners as possible” but British military personnel needed important reassurances before being deployed on a potentially dangerous mission.

“The very least they deserve is to know that they do so on a legal basis and with a proper thought through plan.”

As things stand, that plan does not exist.