AND so it passes with barely a mention. Twenty years ago this week, Britain committed one of the gravest sins in its history: the invasion of Iraq. It was a war based on lies, on the politicisation and corruption of US and UK intelligence services. It was a criminal war, history demands that truth be spoken.

Iraq set the scene for the world we live in today. It shaped the 21st century. Evidently, Iraq wasn’t the primary catalyst for the great tide of history which swept over us. It was the secondary. September 11 came first. No World Trade Center, no Iraq War. One directly caused the other. All historical comparisons are clunky, but we can think of September 11 as the assassination of Archduke Franz Ferdinand in 1914 – the shot heard around the world – and the invasion of Iraq as the First World War: terror triggering a conflict which shapes a century.

The Iraq War shaped me and every citizen in Britain and America. I wrote my first book about the invasion, and called it The War on Truth. Its primary objective was to set down a first draft of history as it happened, outlining the lies told by the governments of Tony Blair and George W Bush to promulgate an illegal war which soaked Iraq in blood.

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Along the way, I speculated about the effects Iraq would have on the western world, and Britain and American in particular. It would clearly lead to a rise of terror in the West, and jihadism in the Middle East, I suggested. There would be a migrant crisis as people fled the war; as a result racism and the far right would proliferate. It would trigger a wave of instability across the Middle East. The invasion would leave the West hamstrung when it came to real risks to security; how could our governments convince us that some future threat was real, when Iraq proved they’d concocted threats?

Iraq would ruin the media, I feared. Nearly all western mainstream media outlets – with notable exceptions such as the Sunday Herald where I then worked as Investigations Editor – parroted lies told by politicians, and were cheerleaders for war. British and American intelligence organisations would also be degraded and crippled through ruthless politicisation by Bush and Blair. How could we believe security services in the future?

Launching a war opposed by the people, I speculated, would be an acid bath for the liberal order; it would collapse the post-war political consensus, as trust in politics detonated, and lead to the rise of populism. Conspiracy theories would proliferate; if people don’t trust the press or politicians, they’d turn to unregulated social media. Iraq, I warned, would be a green light for dictators; if Britain and America could illegally invade another nation, why not Russia or China? Uppermost in my mind was the future for Iraq: terror, sectarianism, endless conflict, countless innocent lives squandered. In the 21st century, Iraq, I believed, was Britain and America’s original sin.

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I also wondered about the effect on British politics. Labour would implode, I predicted. The beneficiaries would be the SNP, Plaid Cymru and the LibDems – all of whom opposed the war.

In 2005, as it started to become clear to British voters that the war was built on lies, Blair clung onto power but saw a huge drop in votes, losing 48 seats. At the next election, in 2010, Labour was swept away. Conservatives took power with LibDems. However, it was the vote that came between those two elections which was to be so significant for Scotland. In 2007, Labour’s coming collapse was presaged at Holyrood when the SNP took power as a minority government.

Scotland had been vociferously anti-war – as had millions across Britain – and the SNP’s opposition to Iraq paid off at the ballot box. Labour had made a pact with the Devil. To steal a line from Christopher Marlowe’s play Doctor Faustus, about the man who sold his soul to Satan: Labour was now dead, “regard its hellish fall”.

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The scene was set for a standoff between Holyrood and Westminster. With Conservatives in power in the wake of the 2008 financial crisis – itself exacerbated by the huge drain on national resources caused by Iraq – we entered the era of austerity. It was a gift to the SNP. Nationalists could establish themselves as the principled opposition to Tory cruelty. That tactic worked so well the SNP won the first majority at Holyrood in 2011 since devolution. And so came the referendum. The shape of Scottish politics was now solely constitutional. For that, thank Blair’s war.

Next was Brexit, itself a shudder from Iraq. It’s evidently absurd to say that terror, migration and distrust of government "experts" – another casualty of Iraq – played no role in the vote. Brexit sustained Scotland’s constitutional deadlock, allowing the SNP to keep hold of power.

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No path in history is ever clear and straight, but we can see a direct trajectory from the invasion of Iraq to the shape of Scottish politics today.

Yet 20 years on, it seems voters have begun to forget the war. Perhaps, then, the SNP’s "Iraq dividend" has finally run dry. A generation has passed since the invasion. Although many, myself included, will never forgive or forget Labour for what it did, it appears plenty of other voters, especially in England, no longer look at the party and see a brand so steeped in blood and shame that they cannot vote for it.

The chaos of 13 years of Conservativism, the party of food banks, has been enough to tamp down memories of what Labour once did in Iraq. It seems inevitable Labour will take power at the next General Election. Simultaneously, the SNP has torn itself apart in this current leadership campaign. It is split and will remain split going into the next Westminster election. Even if the SNP remains dominant in Scottish politics, a more conciliatory Keir Starmer, and the constitutional reform he promises, will drain the independence movement of support.

In the end, though, no matter what happens politically at home, nothing will ever lay to rest the ghosts of Iraq’s dead in Baghdad, Basra, Fallujah and Mosul.