A week on from the Trump travel ban, the absurdity of the Executive Order Protecting the Nation from Foreign Terrorist Entry into the United States is getting clearer. When the White House published the new President’s travel ban last weekend, it appeared to bar almost all nationals from Iran, Iraq, Libya, Somalia, Sudan, Syria or Yemen from travelling to America.

The only such people allowed would be those with a “green card” entitling them to permanent residence in the US, or one of five specific visas for official bodies such as the United Nations. Any normal visitor to the US from one of those countries, whether on holiday, seeing friends and family, or on business, it seemed, was banned. Horribly hardline, but at least clear.

As airlines struggled to make sense of the order, thousands of prospective passengers were turned away from airports across the world because they were regarded as ineligible to travel. Some airlines changed their staff rosters to avoid, for example, an Iranian pilot or Somalian cabin-crew member being assigned to a New York-bound plane.

Forty-eight hours later, though, it turned out that the rules would affect only a tiny number of people.

Late on Sunday evening, the Foreign Office clarified that the ban applied only to people who, in effect, failed two tests. They held a passport from one of the seven countries on Donald Trump’s list, and were also boarding a flight from one of those seven countries to the US.

“If you are travelling to the US from anywhere other than one of those countries (for instance, the UK) the executive order does not apply to you and you will experience no extra checks regardless of your nationality or your place of birth,” said the Foreign Office

Some media misreported that the travel ban was only for direct flights from those seven countries to America. It took about five minutes’ work with the OAG Pocket Flight Guide to Europe, Middle East and Africa to confirm that the grand total of flights from Tehran, Baghdad, Tripoli, etc to the US is zero.

Therefore it must apply only to passengers on connecting flights making “airside” transfers to America. Anyone who went through passport control between flights at Heathrow, Paris, Frankfurt, etc would “reset the clock” by going “landside”. They would be boarding from a service from the UK, France or Germany, rather than one of the seven benighted countries.

You might be thinking, “Surely everyone in that position would just exit the transit lounge and come back in, then?” – but it’s not as easy as that. Even for “airside” transit at Heathrow, for example, not all nationalities are equal.

There are 57 varieties of passports, from Afghanistan to Zimbabwe and including all seven specified nationalities, whose citizens require a visa simply to change planes at a UK airport. The only exception is if they have an impressive visa from another country, such as a US green card; a normal American visa for business or tourism is insufficient.

Given that there’s so much red tape involved when all you want to do is spend a couple of hours drinking coffee or shopping in the transit area, don’t even ask about the complications of landside transit.

Happily, there are plenty of other possibilities. Sudanese people, for example, can make their way across the border to Eritrea, get a visa on arrival, and then check in at Asmara airport for a flight via Cairo, Dubai or Istanbul to a wide range of US destinations. Iranians, Iraqis, Libyans and the rest can find similar workarounds.

The Trump travel ban may be proving as illusory as many other presidential promises, but there are plenty more nations where the barriers are real. Even in Europe, you can be turned away from Serbia if you have a Republic of Kosovo entry stamp in your passport.

Many countries that are mainly Muslim – such as Kuwait, Lebanon and Saudi Arabia – do not allow anyone whose passport indicates they have visited Israel. In my experience Israeli border staff are happy not to stamp your passport, though if you are crossing by land from Jordan or Egypt then the exit stamp will give you away.

Frequent travellers to the region circumvent these restrictions by having two passports (and then trying to remember to present the “right” one). But if you happen to have been born in Israel, regardless of your nationality, the Foreign Office warns you may not be welcome in Saudi Arabia.

India has harsh stipulations for “foreigners of Pakistan and Bangladeshi origins” as well as nationals of those countries. They face a wait of at least seven weeks to obtain a visa.

Perhaps Donald Trump should have studied such hardline policies first. His inept attempt to look tough has proved pathetic.