In a worrying intensification of the crisis in the Strait of Hormuz which saw two tankers disabled by explosions, last night the government of Iran “categorically rejected” US claims that it was responsible for the attacks.

Earlier yesterday, US Secretary of State Mike Pompeo accused the Iranians of unprovoked behaviour which presented “a clear threat to international peace and security, a blatant assault on the freedom of navigation, and an unacceptable campaign of escalating tension by Iran”.

He was not alone in pointing the finger of blame at Iran.

As he addressed a news conference in Washington, Britain’s Foreign Secretary Jeremy Hunt warned that that if Iran was involved in the incident, “it is a deeply unwise escalation which poses a real danger to the prospects of peace and stability in the region”.

READ MORE: ​Britain backs US assessment blaming Iran for ‘attacks’ on oil tankers

As the war of words intensified it became clear that a peace initiative by Japanese prime minister Shinzo Abe had also foundered.

He arrived in Tehran on Wednesday hoping to act as an honest broker between the US and Iran but last night he was on his way back to Tokyo with the mission unaccomplished.

His position was not helped by the fact that one of the damaged tankers, the Kokua Courageous, was Japanese-owned and that the damning US evidence showed video footage of Iranian Republican Guards arriving by patrol craft and retrieving an unexploded limpet mine from the ship’s damaged side.

It was this evidence that led President Donald J Trump to claim on Fox News that the US Central Command video provided him with all he needed to know about who was responsible.

“Well, Iran did do it, and you know they did do it because you saw the boat.” he said. “They didn’t want the evidence left behind . . . It was them [sic] that did it.”

Although Trump insisted that the Iranians were in “deep, deep trouble”, he also claimed that he was in no hurry to act in reprisal and wanted to reopen negotiations aimed at cooling the temperature.

In Washington, Pompeo insisted that US “policy remains an economic and diplomatic effort to bring Iran back to the negotiating table at the right time and encourage a comprehensive deal that addresses the broad range of threats”.

That remains the official line, hence the importance placed by Trump on the Japanese prime minister’s intervention, but it is also true that the US has already sent substantial military and naval assets to the region to defend itself and its allies in the face of further Iranian aggression.

Last month the US deployed the Abraham Lincoln carrier strike group to the Gulf while modern F-35 strike aircraft began arriving at air force bases in the United Arab Emirates.

Accompanying the Lincoln are three destroyers – the USS Bainbridge, the USS Mason and the USS Nitze – as well as the guided-missile cruiser the USS Leyte Gulf.

The deployment followed Washington’s imposition of stringent sanctions on Iran and the blacklisting of the Iranian Revolutionary Guards Corps as a terrorist group.

There are also indications that the US ships could be supported by a smaller British task force led by the Type 23 frigate HMS Montrose which arrived in Bahrain at the beginning of April on a three-year tour of duty in the Middle East.

Naval sources on both sides of the Atlantic insist that, as things stand this weekend, the moves are not warlike in intent but have merely been taken in response to what has been happening in the Strait of Hormuz.

READ MORE: ​Military threats adding to the crisis

However, not for the first time the Trump administration may find that not everyone is marching in step with them.

A spokesperson for German leader Chancellor Angela Merkel said yesterday that it was important to avoid creating a “spiral of escalation”, while the Chinese foreign ministry urged caution and that it was in nobody’s interests to see the crisis degenerating into outright war.

That concern was reiterated by UN Secretary-General Antonio Guterres who told the Security Council last Thursday that the world could not afford “a major confrontation in the Gulf region”.

It all sounds very reasonable.

Neither side wants to provoke a war and, even though the US claims that it has firm evidence that Iran was responsible for last week’s attacks as well as four others made last month, Trump promised US electors that he would not engage in further military adventures in the Middle East.

It is also true that he retains the strongest hand and is probably sincere in maintaining that he wants a peaceful outcome to the crisis.

After all, during the past year, despite provocation from North Korea, he managed to retain a diplomatic equilibrium in his dealings with the excitable President Kim Yung-un over the latter’s possession of nuclear weapons and delivery systems.

Military mathematics also plays a role. In the air and at sea the US outguns Iran, which not only faces an internal financial crisis but also has few allies and many enemies in the Middle East, notably Saudi Arabia, a major Sunni power and key US ally.

Also firmly opposed to Iran is another firm US ally, Israel, which needs no encouragement to be alarmed by the possibility that its neighbour could possess nuclear weapons.

Prime minister Benjamin Netanyahu knows full well that the present crisis is underpinned by Trump pulling the US out of a deal on Iran’s development of nuclear power which seemed to give too much leeway to the Iranians for very little in return.

While the subsequent US sanctions made life difficult for ordinary Iranians, their government seem to have responded by attacking the oil trade lifeline to the west which runs just offshore.

READ MORE: ​Gulf on brink after oil tanker blasts

In that sense it is not the first time that the Strait of Hormuz has been used as a proxy battlefield.

Separating Iran from Oman and the United Arab Emirates, it is only 21 miles wide and is generally held to be one of the most sensitive shipping lanes in the world.

About a third of the global oil trade passes through the choke point each year and the reasoning in Iran seems to be that if sanctions hurt them then they can retaliate by turning off the tap.

So far, the international oil market has responded moderately to the crisis, with prices rising little more than a US dollar a barrel but all that could change if there is any danger of triggering a conflict. And it need not be sparked by violence.

The US and its allies enjoy naval superiority which cannot be matched by the Iranians but in the narrow waters of the Strait of Hormuz there is always the risk of collisions and accidental deaths.

With that comes loss of face, an important consideration in a region where no love is lost between the rival countries and the presence of western powers.

In 2007 15 British naval personnel were taken prisoner by the Iranians after being arrested while on search operations in the Gulf. The incident was described as a “severe embarrassment” and was only ended when President Mahmoud Ahmadinejad announced that they were being released as “a gift to Britain”. In this case no lives were lost but there was no shortage of red faces in the Royal Navy.