A truly alarming situation is developing for the G20 advanced economies. If not handled deftly, its outcome threatens more disastrous consequences for those economies than the events following the oil crisis of the early 1970s. One of the world’s four choke points carrying 20% of its oil and gas has been shut down, and another could easily follow. Nothing like this has ever happened before.

If the religious fanatics of Iran ask their Houthi proxies in Yemen to up the tempo of their strikes in the approaches to the Suez Canal, Europe will shut down. Reserves will be exhausted in a matter of weeks — days in some cases like ours.

How, you might ask, do the mad mullahs have the power to achieve this? The Houthi insurgents of Yemen look to them for their supply of weapons, and both share a visceral hatred of Israel. Altogether, it would represent a doomsday scenario for the embattled democracies.

In such a situation, the gloves would have to come off. Any pretence at playing Mr Nice Guy would end, and the democracies, east as well as west, would feel obliged to offer their military assets to re-open these choke points to save their economies from collapse. It might well be that military occupations of the zones for a period of time would be judged necessary.

It might also be decided for future stability that if boots have to be put on the ground, the opportunity should be seized to rid the world once and for all of the theocratic regime that has brought such murder and disruption to the world. Certainly, the toppling of the regime would be welcomed by a very large majority of the population, its entire sisterhood for a start. As a result, regime change would be unlikely to be a protracted affair.

Sadly, and depressingly for future generations, recent events in Iran have demonstrated that street uprisings can no longer bring down a tyranny if that tyranny is ruthless enough to murder enough people. And that is what the ‘Holy Men’ of Iran were prepared to do — tens of thousands in this case. Only if the men with guns turn against the mullahs can change occur internally. For the moment, the promptly and well-paid 125,000 men of the Revolutionary Guard are, and are prepared to remain, loyal to their master’s dirty work.

As in Afghanistan, and sadly throughout the Muslim world, a high proportion of men quite like their faith’s legitimising male power over women. This explains why the Iranian authorities are able to mount counter-demonstrations. Look for the women among the demonstrators, and you’ll be pushed to find them. But before we get on our high horse, we should remember that our own societies were highly patriarchal only a few generations ago, though this was not mandated by scripture as it is in Islam.

With the USA and Israeli air and naval assault on Iran to neutralise its nuclear and rocketry ambitions, the aims have widened to regime change. But history has taught us that no amount of damage from the air, short of nuclear strikes, can achieve that end. Iranian cities bear no resemblance to those of Hitler’s or our own, come to that. But even so, neither of us considered surrender.

It is a great deal easier to get into things than to get out. If boots on the ground are forced on the West to secure free passage through the straits, then to quote Macbeth, ‘If it were done when ’tis done, then ’twere well it were done quickly.’ And in this case, with such majority hatred of the clerical killers of their sons and daughters, I believe it would be quick. Iranians are a clever and gifted people. There is no reason to believe that if the ghastly, evil regime that has held them in thrall for almost half a century is cast into the dustbin of history, they will not be capable of becoming a normal country and ruling themselves competently. Their civilisation, after all, was once a beacon to the world, tolerant and much admired by Alexander the Great.

The loss of the West’s confidence began with Vietnam. It continued through the fiascos of Afghanistan, Iraq, Libya and Syria. In earlier times there had been triumphs such as the Berlin Airlift, the forming of NATO, the Cuban missile crisis, and the landing on the moon. Going into countries with all guns blazing proved to be the easy bit, but putting together an exit strategy proved altogether harder. Part of the problem was a lack of understanding of the complexities of the regions they were operating in. The Middle East and Muslim world, with its Shia-Sunni divide, was made even more complex by the colonial powers’ ill-thought-out settlement of frontiers following the destruction of the Ottoman Empire. It enabled an entirely new state, Israel, to be set up, creating the thorniest issue of the lot.

Into this china shop has stormed the proverbial bull in the form of the American president. Ironically, Trump’s very unpredictability can sometimes achieve results that plodding diplomacy struggles to keep up with. If the degrading of the bestial regime in Tehran can bring about its collapse, the world and most of all Iranians should rejoice. There is everything to play for, and with luck the world’s most troublesome area may have a chance to settle down, with its remaining tyrants sleeping less easy in their beds.