Today, SNP Education Secretary John Swinney will face a vote of no confidence in the Scottish Parliament over his disastrous handling of the school grades fiasco – which saw 125,000 grades lowered on the basis of schools’ past performance.

As it stands Swinney, who is also Scotland’s Deputy First Minister, is likely to be saved by the Scottish Greens. Yesterday, he announced a complete U-turn on the grading system he introduced – which he said had been intended to ensure teachers’ exam estimates matched up with the previous performance of year groups at their schools. Now no students will be marked down from the grades their teachers awarded them – and no students who were marked up will lose out either.

The Greens apologised for claiming Swinney’s U-turn was singularly the victory of their education spokesperson Ross Greer, before confirming that they will cast their votes to save the architect of the disastrous policy.

Education, at its core, should be a process of liberation that allows children from all backgrounds to fulfil their potential. As democratic socialists, we extend that to the principle that an individual’s place in society is based on their efforts and ability rather than inherited privilege, ethnicity or gender.

For decades, working-class children rose, not out of their class but with their class as the universities and professions became no longer a closed shop for the wealthy. The progress in social mobility made under Labour governments has been under threat for decades through the marketisation of higher education, the defunding of further education and the resurgence of private schooling in England and Wales.

While Scotland has so far managed to avoid a resurgence in state and private schooling there remains an attainment gap, as wide as the Clyde, between children from the most deprived backgrounds and those from the least deprived. This gap is not only deeply unfair but it entrenches privilege and inequality into schooling in Scotland.

Although the First Minister has stated her intentions to bridge the attainment gap, it has continued to grow in Scotland under the stewardship of the SNP. This summer Swinney turned this gap into a yawning chasm. The methodology he introduced was nothing short of an assault on the prospects and life chances of children in the most deprived areas. It also discarded and disrespected teachers’ professional judgement – and it is questionable if the profession will ever trust Swinney’s leadership again.

The reaction to this assault on the most deprived students saw working-class pupils from across the country take to the streets in a defiant assertion of their right to be judged by their merits, not by their postcode. Teachers, familiar with being undervalued by the SNP government, voiced their anger and accused the Scottish government of riding roughshod over their professional judgement.

Both Swinney and First Minister Nicola Sturgeon spent the first five days of the uproar defending their rigged marking system. Working-class school students took to the streets to protest being downgraded. It emerged that in North Lanarkshire, an area I am proud to represent, nearly half of all grades had been revised down due to the socio-economic nature of the area.

Then last Friday, Scottish Labour uncovered an internal SQA timeline for the appeals process – which SNP ministers had spent the last week hailing as the saviour of working-class life chances. The timeline showed that far from providing speedy justice, the appeals system would not give a large swathe of candidates an answer until next May. The timeline was then removed from the SQA’s intranet, and in spite of the exam body’s insistence that it was an error, no alternative date for appeal results was offered up.

We had warned that Swinney’s position would be untenable if he failed to provide a clear plan for getting out of this mess, and this was proof he was not the man to fix it. Swinney jumped into action, offering first an apology and then a remedy – but only when his own job was put on the line.

The Greens may think that means he is fit to continue in office – but Scottish Labour believes this is all the more reason he must go. Of course we welcome the U-turn, but the damage to the self-esteem of working-class young people could be lasting. Whatever our differences on the content of curriculum, surely we can agree that something is deeply wrong when the biggest lesson of all is that it is the career prospects of the Deputy First Minister, and not simply those of 70,000 working-class school students, at stake.

So ahead of today’s confidence vote, I ask Nicola Sturgeon to reflect on her own words 20 years ago, the last time there was a controversy around SQA results. This was an episode which affected 600 students, not the 70,000 downgraded this time round. It was an error, not a conscious policy choice that the opposition had warned about for four months before. “I want Sam Galbraith out of office, not off the hook,” Sturgeon said of the Labour education minister of the time. Hand on heart, can she tell us why she wants John Swinney off the hook, not out of office?