The decision announced by a judge in the British overseas territory of Gibraltar Thursday to release an Iranian oil tanker Grace 1, seized by the British Royal Marines on July 4, was taken despite a last-minute intervention by the US Justice Department.

The US authorities used an email sent at 1:30 in the morning to communicate their demand that the ship be held so that Washington could file its own pseudo-legal case for taking control of it.

Chief Justice Anthony Dudley of Gibraltar’s supreme court ruled Thursday afternoon that there were no legal grounds for continuing to hold the tanker, which had been seized on the pretext of enforcing unilateral sanctions imposed by the European Union—which Britain is deserting—against the shipment of oil to Syrian facilities controlled by the government of President Bashar al-Assad. The judge likewise dismissed the US demand, saying that no legal papers had been filed with the court.

The Iranian government, following negotiations with British officials in London, issued a formal letter to the authorities in Gibraltar pledging that the Grace 1 would not deliver its load of 2.1 million barrels of crude oil, valued at $140 million, to any “entity” proscribed by the EU sanctions. Tehran indicated that the ship would sail to an unspecified destination in the Mediterranean.

The EU anti-Syrian sanctions were merely a pretext for what amounted to an act of piracy by the British military. Spain’s Foreign Ministry and other diplomatic sources have revealed that the action was carried out at the behest of Washington as a means of ratcheting up tensions under conditions in which US provocations have placed a war in the Persian Gulf on a hair trigger.

The war drive has been initiated entirely by Washington, beginning with the Trump administration’s May 2018 abrogation of the Iran nuclear accord signed between Tehran and the major world powers. It re-imposed a sanctions regime that is tantamount to a state of war, while announcing a “maximum pressure” campaign aimed at reducing Iranian oil exports to zero.

This was followed by a military buildup in the Persian Gulf, with the deployment of a carrier battle group along with a B-52 bomber strike force and the drafting of plans to send 120,000 US troops to the Middle East in the event of war.

The threat of a full-scale war that could quickly drag in the major powers was made clear in June when President Donald Trump revealed that he had come within 10 minutes of launching devastating air strikes on Iranian targets in retaliation for Iran’s downing of an unmanned US spy drone.

The British seizure of the Grace 1 was followed barely two weeks later by Iran’s seizure of a British-flagged oil tanker in the Strait of Hormuz. Iranian authorities charged that the tanker, the Stena Impero, had violated numerous regulations while sailing in Iranian waters, hitting a fishing boat, turning off its transponder and refusing to respond to Iranian authorities. London dismissed the charges, insisting that there was no comparison between the “legal” seizure of the Grace 1 and the “illegal” and virtually identical taking of the Stena Impero.

There has been widespread speculation that the release of the Grace 1 would be reciprocated by the release of the Stena Impero.

Iranian authorities cast the decision in Gibraltar as a humiliation for Washington. Iran’s ambassador to the UK, Hamid Baeidinejad, tweeted, “Up to the last minute, the United States tried in vain to prevent the release of the tanker, but was faced with a humiliating defeat.”

Tehran’s Foreign Minister Mohammad Javad Zarif denounced Washington’s intervention. “Having failed to accomplish its objectives through its #EconomicTerrorism—including depriving cancer patients of medicine—the US attempted to abuse the legal system to steal our property on the high seas,” Zarif tweeted on Thursday. He added: “This piracy attempt is indicative of Trump admin’s contempt for the law.”

There is no guarantee, however, that the UK will not in the end bow to Washington’s demands. While the Grace 1 is legally free to leave Gibraltar, it is still waiting to assemble a crew. Those seized at gunpoint by the Royal Marines—including Indians, Filipinos, Russians and Latvians—have been imprisoned for 40 days.

While Gibraltar’s Chief Minister Fabian Picardo issued a video statement declaring that the Grace 1 had been “released from detention” as a result of Tehran’s pledge to comply with the EU sanctions, he added that the British territory’s mutual legal assistance authorities would make “an objective, legal determination” of any US demands to impound the ship.

US national security adviser John Bolton, who has been a principal advocate of the escalation of US aggression against Iran, was in London earlier this week, praising Britain’s recently appointed prime minister, Boris Johnson, for joining the US war fleet targeting the strategic Strait of Hormuz, the crowded 21-mile-wide sea lane through which one-fifth of the world’s oil supplies passes.

Dubbed “Operation Sentinel” by the Pentagon, the naval patrols off the coast of Iran have been billed as an international effort, but thus far, the UK is the only country to provide any significant assets.

Before the coming to office of Johnson, who has sought close ties to the Trump administration based upon their shared hostility to the EU and hopes of a US-UK post-Brexit free trade deal, Prime Minister Theresa May and her foreign secretary, Jeremy Hunt, had called for a “European-led maritime protection mission”, rather than joining the US intervention. This was in keeping with the UK’s continued support—along with that of France and Germany—for the Iran nuclear deal that Washington has repudiated.

It is difficult to imagine that Bolton, who had celebrated the British seizure of the Grace 1, did not talk with British officials about the fate of the ship when he was in London.

A decision by London to allow the US to seize the Iranian vessel after ruling that it was free to sail from Gibraltar would likely be answered in kind by the bourgeois-clerical regime in Tehran, which is facing increasingly untenable economic conditions created by US sanctions and the threat of social upheavals from below. Further Iranian seizures of tankers would set the stage for a military confrontation in the Gulf.

All of Washington’s actions are aimed at provoking such a war. The aim of US imperialism is regime change in Iran as part of a relentless campaign to assert American hegemony over the Middle East and its energy reserves in order to control access to them by other major powers, particularly China. It is this strategic objective that makes a military confrontation between the US and Iran the potential antechamber of a Third World War.