Great. Just what we need. Our self-styled key ally in the so-called war on terror – Saudi Arabia – just closed the airspace, land and sea borders with our other ally, Qatar, accusing it of supporting Isis. What’s that about?

Well, like almost everything in the region, it is about the strategic duplicity of the West, exacerbated by the childlike idiocy of the US president. Does it matter for Brits – other than those stuck at airports in the Gulf, or policy wonks obsessed with Middle Eastern conflicts?

It matters on every street in Britain.

Saudi Arabia, Qatar and the other Gulf monarchies, organised in the so called Gulf Cooperation Council (GCC), have a long history of backing the spread of Sunni Islamist ideology outside the region. Not just in Britain, but, for example, even in places such as rural Nigeria, where I’ve seen Gulf oil money used to incentivise Christians to convert, fuelling the religious conflict there.

But the Qataris have always punched above their weight in regional affairs, and displayed a more intelligent grasp on the strategic, demographic and cultural changes sweeping the Arab world.

It was the Qataris who set up Al Jazeera, as a counterweight to the reactionary state media across the middle east, and to challenge the US media’s right to set the global narrative about the Islamic world.

Qatar supported the short-lived Muslim Brotherhood government in Egypt and still supports and shelters the leaders of the Hamas government in Gaza. In Syria, Qatar spent up to $3bn (£2.3bn) in the first two years of the civil war bankrolling the rebels – allegedly including the al-Qaida-linked group al-Nusra Front.

The Saudis, too, bankrolled Islamist rebels, and both sides claim never to have bankrolled Isis. So what is really at stake?

The issue torturing the Saudi monarchy is Iran. Obama made peace with Iran in 2015, in the face of Saudi and Israeli opposition. Qatar is diplomatically closer to Iran. It has also supported (outside Qatar) the spread of political Islam – that is, of parties prepared to operate within nominally democratic institutions.

The Saudis’ strategic aim, by contrast, is to end the peace deal with Iran and to stifle the emergence of political Islam full stop.

Last month, Donald Trump took himself to Riyadh to participate in a sword dance and glad hand the Saudi royals. And that is where the trouble escalated.

Qatar’s ruler had been reported by his own state media as warning against the escalating confrontation with Iran: “Iran represents a regional and Islamic power that cannot be ignored and it is unwise to face up against it,” said a TV tickertape quoting the Emir.

When these comments caused outrage in Riyadh, the Qataris withdrew them, claiming they had been “hacked”.

But Trump’s visit poured ethanol on to the simmering conflict. Few observers see today’s move as anything other than the Saudis acting with state department backing. One Iranian official tweeted the spat was “the prelimary result of the sword dance”.

Saudi Arabia is meanwhile prosecuting a war on Iranian-backed rebels in Yemen, using more than £3bn worth of British kit sold to it since the bombing campaign began. In return, it has lavished gifts on Theresa May’s ministers: Philip Hammond got a watch worth £1,950 when he visited in 2015. In turn, Tory advisers are picking up lucrative consultancy work with the Saudi government.

The problem remains Saudi culpability – past and present – for funding islamist terrorism. After September 11, the Saudi monarchy did begin to crack down on islamist terrorism domestically, criminalising terrorist finance. But, as a US cable released by Wikileaks shows, even as late as 2009, that “donors in Saudi Arabia constitute the most significant source of funding to Sunni terrorist groups worldwide”.

Since the coronation of King Salman in January 2015, there has been a programme of economic modernisation and political reforms the monarchy has tried to sell as liberalisation.

However, Salman has also escalated the Yemen war and escalated tensions with Iran – most notably by executing a prominent Shia cleric and 46 other opponents last year.

In Britain, when the Lib Dems in the Coalition supported airstrikes against Isis, the price they extracted was for Cameron to launch an inquiry into foreign funding of terrorism. Eighteen months on, it remains suppressed. As with the infamous Serious Fraud Office investigation into corruption at BAE, it is being buried because it would expose the past misdemeanours of the the Saudis.

We do not know why Britain has suddenly become the target for a jihadi terror surge: five foiled attempts and three gruesomely successful ones in 70 days.

One possible explanation is that, with the increased tempo of fighting in Mosul and towards Raqqa, it is becoming clear to the thousands of jihadi fantasists sitting in bedrooms across Europe, that their “caliphate” will soon be over.

If so, the question arises: a) what will replace it on the ground and b) how to deal with the survivors as they fan out to do damage here?

In both cases, it is vital that the Gulf monarchies funding the Syrian resistance are on board with the solution. And, as of today, two of the key players are waging economic war and a bitter rhetorical fight with each other.

As for the wider world, it is Iran that emerges as the tactical victor in today’s spat. Trump flew to Riyadh and the result was air transport chaos across the Gulf. Iran had an election and the moderates won.

But there is good news. If Jeremy Corbyn is prime minister on Friday, Britain’s game of thrones in the Gulf will end. The foreign policy he outlined at Chatham House represents a complete break with the appeasement of terror-funding Saudi autocrats. The strategic defence review he has promised would unlikely keep funding the Royal Navy base in Bahrain.

Britain cannot solve the diplomatic crisis in the Gulf. But it can stop making it worse. Last December, Boris Johnson inadvertantly had a go. He named the Yemen conflict as a proxy war; accusing both the Saudis and Iran of “puppeteering”. He was quickly slapped down.

Only a Labour government will stop appeasing the Saudi monarchy and reset the relationship to match Britain’s strategic interest – not the interest of Britain’s arms dealers and PR consultants.