What on Earth were the British politicians and officials thinking who gave the go-ahead for the seizure of the Iranian oil tanker Grace 1 off Gibraltar on 4 July? Did they truly believe that the Iranians would not retaliate for what they see as a serious escalation in America’s economic war against them?

The British cover story that the sending of 30 Royal Marines by helicopter to take over the tanker was all to do with enforcing EU sanctions on Syria, and nothing to do with US sanctions on Iran, was always pretty thin.

The Spanish foreign minister, Josep Borrell, has said categorically that Britain took over the tanker “following a request from the United States to the United Kingdom”.

One fact about Iranian foreign policy should have been hardwired into the brain of every politician and diplomat in Britain, as it already is in the Middle East, which is that what you do to the Iranians they will do to you at a time and place of their own choosing.

The US and UK backed Saddam Hussein in his invasion of Iran in 1980, but this was not unconnected – though it was impossible to prove – with the suicide bombing that killed 241 US service personnel in the marine barracks in Beirut in 1983.

Scars on Middle East landscape bear witness to past peace failures Show all 16 1 /16 Scars on Middle East landscape bear witness to past peace failures Scars on Middle East landscape bear witness to past peace failures A Syrian tank lies turned over in the Hermon Stream in the Banias Nature Reserve on the western edge of the Israeli-occupied Golan Heights. Israel captured the area, a former demilitarized zone, in the 1967 Six Day War Reuters Scars on Middle East landscape bear witness to past peace failures A part of the trench in a former Jordanian military post known as Ammunition Hill in Jerusalem. Originally built by the British, the site was captured by Jordan in the 1948-1949 war and held by them until Israeli troops captured it in the 1967 Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures An abandoned mosque on a rainy morning in the Golan Heights, in territory that Israel captured from Syria and occupied in the 1967 Middle East war. Until 1967 a Syrian village inhabited by Circassians stood near the site, which now lies just 5km on the Israeli side of the United Nations-monitored 'Area of Separation' that divides Israeli and Syrian military forces under a 1974 ceasefire arrangement Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures The broken helicopter of the late Palestinian Authority President Yasser Arafat sits atop a structure in Gaza City. Without its main rotor, it is now on public display in the coastal enclave that is now controlled by the Palestinian Authority's most powerful domestic rival, Hamas Reuters/Ibraheem Abu Mustafa Scars on Middle East landscape bear witness to past peace failures A sign warning of landmines on a fence in the Golan Heights. Many Israeli and foreign tourists drive past the site on their way to popular holiday spots Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures Part of an abandoned Syrian building in the Golan Heights. Once a military headquarters, it is one of many Syrian buildings left deserted and abandoned since wars fought half a century ago Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures The wall of a structure in a former Syrian outpost in the Israeli-occupied Golan Heights. In stark contrast to the beauty of the surrounding countryside, it is now crumbling and covered in graffiti, one Arabic message reading: "The Syrian army passed by here." Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures Buildings constructed during the British Mandate era to serve as jails and fortified positions in Al-Jiftlik village near Jericho, in the Israeli-occupied West Bank. Long abandoned, sheep now wander through the empty buildings, searching for vegetation in the scorching heat of the Jordan Valley. The Israeli military sometimes uses them for training, Palestinian residents say Reuters/Mohamad Torokman Scars on Middle East landscape bear witness to past peace failures A bunker in the Golan Heights, in territory that Israel captured from Syria. It was used for military purposes and has been deserted for many years Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures British soldiers depicted in a mural on an old pillbox in Jerusalem. The pillbox dating back to the era of British Mandatory rule before 1948, stands abandoned in a busy intersection of Jerusalem. The mural was added in recent years Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures Concrete blast walls are seen in an open area once used by the Israeli military near Rahat, southern Israel. Once part of a facility for training in urban warfare, the barriers are now an isolated scar on the landscape Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures A part of a trench is seen in a former Jordanian military post known as Ammunition Hill in Jerusalem. Originally built by the British, the site was captured by Jordan in the 1948-1949 war and held by them until Israeli troops captured it in the 1967 Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures The derelict remains of Gaza International Airport in Rafah in the southern Gaza Strip. Former US President Bill Clinton attended the opening ceremony in 1998. But Israeli air strikes and bulldozers closed it down during the second Palestinian uprising, or Intifada, a few months after the September 11, 2001 attacks on the United States Reuters/Ibraheem Abu Mustafa Scars on Middle East landscape bear witness to past peace failures A house is seen in Lifta, a ruined Palestinian Arab village whose inhabitants left or were forced from their homes in the conflict that accompanied the end of British rule and the founding of Israel in 1948. The abandoned ruins are visible to travelers arriving at the western entrance of Jerusalem Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures An abandoned mosque on a rainy morning in the Golan Heights, in territory that Israel captured from Syria Reuters/Ronen Zvulun Scars on Middle East landscape bear witness to past peace failures A part of a structure in a former Jordanian military base near the Dead Sea in the Israeli-occupied West Bank. The building is a scar in the landscape as it stands deserted following the 1967 Middle East war when Israel captured the area from the Jordanians Reuters/Ronen Zvulun

Commentators seeking an explanation for the UK’s seizure of the Grace 1 suggest that it was suckered into the action by super hawks in the US administration, such as the national security adviser John Bolton.

But, given the inevitability of the Iranian reaction against British naval forces too weak to defend British-flagged tankers, the British move looks more like a strategic choice dictated by a lack of other options.

Confrontation with the EU over Brexit means that Britain has no alternative but to ally itself ever more closely to the US.

Of course, this will scarcely be a new departure since Britain has glued itself to the US on almost all possible occasions since the Suez Crisis of 1956.

The lesson drawn from that debacle by Whitehall was that the UK needed to be always close to the US. The French drew the opposite conclusion that it must bond more closely with the continental European states in the shape of the European Economic Community.

The one-sided relationship between the US and UK was in operation in the military interventions in Iraq and Afghanistan. Britain walked into these quagmires to demonstrate its position as America’s most loyal ally while lacking a coherent policy and without adequate forces.

Authorities continue to detain Iranian tanker Grace 1 (AFP/Getty) (AFP/Getty Images)

The Chilcot report said the only consistent theme that it could detect in British policy in Iraq between 2003 and 2009 was how to get its troops out of the country. Wanting to do it without offending the Americans, the British – in a major miscalculation – decided that this could be best done by relocating their forces to Afghanistan, where more than 400 of them were killed in action.

In its confrontation with Iran, Britain is in trouble because it is trying to ride several horses at the same time. It is supposedly seeking to adhere to the Iran nuclear deal and oppose US sanctions on Iran, but in practice it has done nothing of the sort and boarding the Grace 1 was a clear demonstration of this.

UK-Iran radio exchange released after tanker seized in Gulf

One feature of the present crisis is that the seizure of the Stena Impero is clearly tit-for-tat by Iran. It is, unlike past Iranian retaliatory actions, making no effort to conceal this, presumably calculating that there is not much Britain can do about it and it is a good time to demonstrate Iranian strength and British weakness.

Iran expresses no doubt that Britain is acting as a US proxy, though this has been true for a long time. But life as a proxy may be particularly dangerous in the Gulf at the moment because of the peculiar nature of the confrontation between the US and Iran in which neither side wants to engage in an all-out war.

This makes it necessary to act through proxies like the UK, an approach that minimises the chances of Americans being killed and Donald Trump having no option but to retaliate in kind.

Iran is being visibly hurt by sanctions but Iranians are more likely to blame the US for their sufferings than their own government. The US is not going to launch a ground invasion, as it did in Iraq in 2003, and, so long as this is off the table, Iran can sustain the military pressures.