Iran has won a point over the UK.

Seizing a British oil tanker in the gulf has been always a red line. The Iranians have pushed the UK’s back against the wall, as they said they would do. Their message was loud and clear. But British ministers and diplomats underestimated the Iranian threat.

The confrontation started with the confiscation of the Iranian oil tanker Grace 1 in Gibraltar, on behest of the US. Trump’s pressure on the government was meant to drive a wedge between the UK and its European allies, who are keen on maintaining the status quo and the 2015 nuclear deal, signed by Iran and other major powers.

The EU signatories want Iran to avoid two crucial events: Iran breaking off from the nuclear accord (also known as the JCPOA), and igniting a war with the US.

As for the Iranians, their trigger-happy attitude in the gulf aims to nudge the Europeans out of their comfort zone. They want EU states to pressure the Trump administration to scale back some of the economic sanctions, especially on Iran’s oil sales, since Trump pulled out of the JCPOA and re-imposed them on Iran.

Tensions high as Trump approves new Iran sanctions: In pictures Show all 17 1 /17 Tensions high as Trump approves new Iran sanctions: In pictures Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, their surface-to-air missile is seen as it shoots down a US surveillance drone EPA Tensions high as Trump approves new Iran sanctions: In pictures This photo shows US RQ-4A Global Hawk unmanned surveillance drone. A drone of this model was shot down by Iran on Thursday 21 June AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures An oil tanker is on fire after it was subject to a suspected attacked at the Gulf of Oman on June 13. The US has blamed Iran for the attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures US President Trump holds up a signed executive order to increase sanctions on Iran on 24 June AP Tensions high as Trump approves new Iran sanctions: In pictures Iranian President Rouhani stated in a televised address that the White House is "afflicted by mental retardation" following the increase in sanctions on 25 June EPA Tensions high as Trump approves new Iran sanctions: In pictures An Iranian navy boat tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures A screenshot from a video released by the US Department of Defense that the US claims to show Iranian removing an unexploded limpet mine form the hull of the Japan-owned ship that was attacked in the Gulf of Oman on June 13 Getty Tensions high as Trump approves new Iran sanctions: In pictures An item reportedly found on the Japan-owned oil tanker that was attacked on June 13 in the Gulf of Oman AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures A handout photograph from the US Department of Defense shows a composite material that the US claim was left behind on the hull of the Japan-owned oil tanker following the removal of an unexploded limpet mine Getty Tensions high as Trump approves new Iran sanctions: In pictures A view from the cabin of an Iranian navy boat as it tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack EPA Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The picture suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The pictures suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack EPA

The Iranian regime also doesn’t want any of the three EU signatories (the UK, France and Germany) to pull out of the deal. The EU partners are vital for Iran because they provide it with a moral, political and diplomatic cover against aggression from the US. They also help to thwart the repeated and relentless attempts by Russia and China (the non-European signatories) to isolate Iran from Europe, and increase its dependence on them. And the EU partners stand in the way of Trump’s international coalition, whose outcome could well be an exact reflection of the lead up to the Iraq War in 2003.

By seizing tanker Stena Impero, Iran has placed all its strategic and intertwined interests with the EU on the line – in a bid to pressure Trump.

But pressuring Trump is a very complex and extravagant business. Trump must have rejoiced when he received the news about the Revolutionary Guard Corps seizing a British tanker. The American President want the Europeans to join his anti-Iran coalition.

The Iranians understand the UK’s strategic weaknesses and political vulnerabilities, and they play them well against the UK’s increasingly out of touch political establishment, which is utterly burned out by Brexit.

The timing of seizing the tanker has been carefully chosen. Amid the changing of the political guard, Iran understands that the UK is realistically unable to build up a consensus as to how it should push back against Iran’s bullying its maritime merchant fleet at the Strait of Hormuz.

This will be the first order of business for future PM Boris Johnson, whose diplomatic skills will be instantly put to the test. He might clumsily rush to follow the example of the Falklands War, when Margaret Thatcher’s esteem was very low, and she, through determination and ruthlessness, managed to rise out of the war’s ashes as an exceptional leader.

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But Johnson is not Thatcher, and this time the US is no longer there.

If he becomes our next prime minister on Tuesday, Boris will likely propel the UK to fall in line with the US strategy on Iran. This is where trust with Iran will face an absolute annihilation.