When it comes to judging how well their governments are performing, the Scottish public have plenty of different measurements to choose from.

But in the case of the current SNP Scottish Government, they made this choice a lot easier for the Scottish public when they declared, with great confidence, that they want to be judged on education.

At the time, this was a welcome mission statement from a government who rarely seem capable of focusing on anything other than independence. But given how the Scottish education system has turned out since then, it is a statement they will now be regretting.

Nowhere is the state of Scottish schools clearer than with the recent PISA results released this month.

The PISA study compares the performance of nearly 700,000 pupils from 81 separate countries and is one of the most respected international comparisons between different countries’ education systems.

But the most recent set of results from PISA showed that Scotland’s score in both maths and science has now reached its lowest ever level – and is now below the UK average. Even in reading, Scotland’s score is now lower than England’s and hasn’t increased at all since the record low score seen in 2015.

Of course, the SNP were keen to point out that the PISA results are just one way of measuring education, and that there are many other ways to measure the overall health of the Scottish education system.

The problem with this response though, is that no matter how you look at things, Scottish schools appear to be going backwards.

For example, further data published earlier this month shows that the attainment gap between the richest and poorest pupils in the country has barely changed at all since 2019, and in numeracy it has even increased.

Of course, we would have even more data on how Scottish education compares to the rest of the world if the SNP hadn’t removed us from two other international comparisons to avoid further scrutiny.

This SNP Scottish Government had all the ingredients to create an education system that maintained – and even built on – its world class status. We have some of the best teachers in the world, incredibly talented youngsters, and a curriculum with plenty of potential behind it.

However, despite their claims that education is their main priority, and despite throwing countless different Education Secretaries at this issue over the last 16 years, the SNP have managed to take these key ingredients and produce a result that is average at best.

This government once made all the right noises on education, and people could be forgiven for believing that the SNP actually meant what they were saying. But after 16 years of decline, the game is now up.

Parents, pupils and teachers may once have trusted this government to safeguard Scotland’s once great education system. But after the legacy the SNP will leave behind on this issue, they will never be trusted again.