Jeremy Corbyn will suggest today that British foreign policy causes Islamist terror attacks here at home.  Certainly, it would be absurd to claim that there was no connection at all between western military action in Iraq and Afghanistan and 7/7, or 21/7, or the attempted terrorist attack on Glasgow Airport in the same year, 2007.

But is is worth pausing at the start, as the Labour leader seeks to get ahead of his critics, to ask what our foreign policy is now, rather than what it was ten years ago.  We have withdrawn our soldiers from Iraq and Afghanistan.  We have no boots on the ground in Syria.  Indeed, the Government has spent a lot of time and trouble trying to persuade Russia to ditch Assad, the mortal enemy of Islamists like Salman Abedi, the perpetrator of the Manchester atrocity.  Mention of Abedi takes us to Libya, the country from which his Islamist father fled in 1992 to escape Gaddafi before Britain gave him and his family asylum.  A decade or so later, David Cameron’s Government played an indispensable part in the overthrow of the dictator who that father hated.

The main Islamist force against which our armed forces are engaged in military action today is ISIS, the terror group which is attempting to form a pre-modern state in Iraq and Syria, complete with bans on music at parties,  the teaching of evolution in schools, and  the display of photographs in shop windows and women appearing in public – all complemented by forced conversions, the murder of prisoners of war, religious cleansing, floggings, rapes, stonings, the throwing of people from tall buildings, beheadings, crucifixions, burnings-alive and the use of children as suicide bombers.  All this is expended on Alawites, Yazidis, Druze, Christians, Shia Muslims and indeed anyone ISIS disapproves of, including very many of their fellow Sunni Muslims.

A moment’s thought will confirm that there is no foreign policy Britain could introduce that could possibly appease the likes of Abedi.  We are damned if we intervene, and damned if we don’t.  If we intervene, we are accused of imperialism and wars for oil.  If we don’t, we are accused of indifference to the plight and slaughter of Muslims.  Either way, we lose.

But in any event, foreign policy is not, repeat not, the sole or even the main cause of Islamist terror.  The twelve people murdered in the offices of Charlie Hebdo were not slaughtered because of France’s foreign policy. They were killed because the magazine had run cartoons of Mohammed.  Kurt Westergaard had nothing to do with Denmark’s foreign policy.  But he was one of the Danish cartoonists who had also dared to draw such a cartoon – and was duly assaulted with an axe.  The women fingered for slaughter in “for example, the biggest nightclub in central London” had nothing to do with foreign policy either.  “No-one can even turn around and say ‘Oh they were innocent,’ – those slags dancing around,” said Jawad Akbar a member of the gang that plotted mass murder.

Military intervention, non-intervention, secular government, liberal democracy, the rule of law, an independent judiciary, women’s freedom, gay rights, Jews, Shia Muslims, Sufis, the technological superiority of the west, the backwardness of much of the Muslim-majority world – all these assemble in the minds of Islamist fanatics, like a collage on a teenager’s wall, to provoke a primal scream of fear and hatred.  That many of them have previous form as criminals and addicts, are not in a stable relationship, and come from broken families shovels fuel on the fire.  And just as there is no foreign policy that could appease people like these, so there is no domestic policy either, short of handing them Muslim-majority enclaves of our cities to govern, and wishing them the best of British.

To point all this out to much of the Left, however patiently, is to meet accusations of racism and Islamophobia.  Since the facts are incompatible with its worldview, which is shaped by a sense of adolescent protest, the facts must therefore be wrong. So it must stop its ears.

ISIS’s barbarity is too noxious even for Corbyn’s stomach.  But there is scarcely another terror group that he has not presented, during his 40 long years in politics, as morally equivalent to British demoracy.  Hamas, Hezbollah, the IRA – he has cuddled up to the lot.  Doing so has not been, as it is for some politicians on the far Left, incidental to his main political interests.  Explaining away terrorism has been an abiding political fixation – from those press conferences with Gerry Adams during the 1980s though welcoming his Hezbollah “friends” to Parliament eight years ago to his engagement of Andrew Murray, of Stop the War, as an aide for this election.  That Corbyn never once condemned an IRA atrocity during its terror campaign will be long remembered.

Boiled down to his essence, Corbyn is Peter Simple’s Dr Heinz Kiosk, with his catchphrase of “we are all guilty”.  When push comes to shove, the west must be wrong – or so he cannot help thinking, because that thought has been integral to his best part of half a century of political agitating.  This is the man who got on the ballot paper for Labour’s leadership election because the likes of Frank Field and John Cruddas and Margaret Beckett put him there, believing he couldn’t win.  This is the leader in whom Labour MPs passed a no confidence motion, by 172 votes to 40.  Since they have no confidence in this lifelong apologist for terror, this renouncer of our nuclear deterrent, how can they now ask the British people to vote for him?