The SNP has been accused of pushing "anti-UK propaganda" about schools in an independent Scotland, as the party gears up to launch its 12th independence paper.
The paper will be centred around "education and lifelong learning" in an independent Scotland.
Scotland's averagereading score fell by 11 points to 493 at the latest Pisa scores, as compared with 2018. It also lags behind England’s score of 496.
For maths and science, Scotland fell below average, scoring 471 and 483 respectively, another decline from 2018.
Ahead of its publication, Pamela Nash, chief executive of Scotland in Union, accused the Scottish government of being "obsessed with a negative campaign to divide Scotland".
She said: "Education is fully devolved to the Scottish Parliament and the SNP has ruined our reputation for excellence, with Scotland plummeting down the international tables. The decline in reading, maths and science means we have fallen behind England.
"This is what happens when you have a nationalist government obsessed with a negative campaign to divide Scotland and take away opportunities for our young people, rather than a government focused on creating opportunities for the next generation in our interconnected world.
"The people of Scotland want politicians to focus on what really matters, not waste taxpayers' money on yet another piece of anti-UK propaganda."
Scottish Liberal Democrat education spokesman Willie Rennie added: "I can't decide if this is an outrageous waste of taxpayers' money that would be better spent in schools or just another boring yawnfest. Either way Jamie Hepburn must have something better to do."
Scottish Education Secretary Jenny Gilruth will visit a nursery garden in Fife today, alongside independence minister Jamie Hepburn to launch the latest independent paper.
Earlier this month, Scottish Conservative Leader Douglas Ross has said he is worried for his children's future after a "year of failure" from Humza Yousaf.
He hit out at the SNP for "excessive spending on the wrong priorities and the failure to enact any positive change".
The MP pointed to a decline in Scottish school standards, saying he is worried the education of his two sons "will be significantly less than the education that I got in Moray".
Speaking to the Scottish Express, Ross warned: "I think Scots are scunnered with the SNP. They are absolutely fed up with the wastage they see from the Scottish Government, that excessive spending on the wrong priorities and the failure to enact any positive change.
"I'm worried about my two boys' education that they will get in Moray, which at the moment looks like it will be significantly less than the education that I got in Moray.
"I'm worried for family members and constituents and people in every part of Scotland who are facing excessive waits on the NHS.
"I'm worried for our businesses that don't get the support from the Scottish Government, even though the SNP/Green government have been given additional funding to help businesses in hospitality, leisure and tourism."
LATEST DEVELOPMENTS:
He added: "It's now two years in succession that the SNP government have failed to pass on the benefits of the business tax rates reduction for these purposes in those sectors, and that's inexcusable. People are rightly angry, annoyed and just fed up with this government.
"There is no doubt that Scotland was a world leader in education and we have fallen down the rankings, my sister is a teacher in Moray at the money and I know how difficult it is for teachers right now, so for Jenny Gilruth to say she has not even read a report about violence in schools, it shows they are not taking the issue seriously."
GB News has contacted the SNP for comment.
