This week there has been a new development in the mutual exchange of threatening words and deeds between Iran and the United States, but now London is involving itself, and becoming entangled in military plans. It is impossible to imaging that the present situation will calm down, particularly since rabid Brexiteer and Donald Trump supporter Boris Johnson is, not surprisingly, expected to become the next British prime minister in a few days, following Theresa May's resignation.

The evidently credible facts are that Wednesday, July 10, three Iranian ships attempted to “impede the passage” of a BP shipping tanker in the strategic Straits of Hormuz on its way to the Iraqi port of Basra. In response, a British Royal Navy frigate that was escorting the tanker intervened between the tanker and the Iranian vessels with guns pointed, forcing the Iranian ships to turn away.

Tehran denies that it caused this incident, a denial that does not really stand up given that it followed an incident last week in which the U.K. halted an Iranian vessel near Gibralter on the grounds it was transporting crude oil to the Baniyas Refinery in Syria in violation of EU sanctions. Iranians called the British action piracy. That Iran’s recent action was a reprisal for Britain's is thus entirely plausible, particularly since not only Tehran but Madrid claims that the British acted at Washington’s request.

The episode, which gave rise to a new round of threats on Friday, July 12, comes on top of increasing acts of aggression in recent weeks, including the sabotage of tankers and the downing of an American drone. Understandably, the world would not be so shaken by these tensions had Trump not determined that the 2015 Iran nuclear deal did not sufficiently limit Iran’s nuclear development, and instead withdrew from the deal last year and reimposed sanctions that are strangling Iran's general economy. This strategy prevents Iran from selling its oil and keeps it isolated, which is what the Saudis and Israelis want.

The result has been that ordinary Iranians suffer, and suffer terribly, while the theocratic regime that runs the country remains firmly in power. In response to actions in the Persian Gulf that restrict its oil flow, Iran is taking measures calibrated to break with the nuclear deal, such as its declaration on Monday, July 8, that it was going to enrich uranium. All these actions, however, are reversible.

Between Iran's refusal to be intimidated and Trump's “maximum pressure” campaign, such shows of force will become worse before gunboat diplomacy gives way to rational negotiation. Will there be war? Probably not, according to qualified experts. There is, however, no doubt that the danger from these naval encounters will increase with Washington's announcement that it plans to quickly create an international military force to assure freedom of navigation in the Persian Gulf.

This places Great Britain in an increasingly ambiguous situation. With the support of London and Berlin, two other signatories to the Iran nuclear deal, Paris has undertaken the difficult mediation required to calm things down and save the deal, if such a thing is still possible. The recent surge in hostilities makes it seem unlikely that London's commitment to the deal is stable, though.

Such a shift could become worse given the polemics surrounding the recent resignation of Britain's ambassador to Washington, Kim Darroch, which followed the leak of his cables to London describing the Trump administration as “inept” and “dysfunctional.” With his refusal to defend the British ambassador, Britain's likely next prime minister, Johnson, has shown himself to be subordinate to Trump in order to secure a free trade deal with the U.S. once Brexit is finalized, much to the dismay of the Foreign Office and most of Britain's politicians.

Following Johnson's reasoning, Martin Kettle at The Guardian has written that Britain risks becoming a “vassal of a capricious unilateralist state,” making the future prime minister “Britain's Carrie Lam to Washington's Xi Jinping.” Still, this act of becoming a vassal has at least one historical precedent: Tony Blair's submission to George W. Bush's Iraq War and to all its lies.