The SNP's record on education while in government is a "mark of shame" upon the country, according to the Scottish Conservative leader.

Ruth Davidson will call the SNP's performance in running Scotland's schools an "utter disgrace" during her address to the Scottish Conservative conference later on Saturday.

In December, it was revealed 12 countries performed better than Scottish children in reading and science including England, Australia, Estonia, Finland and Slovenia, the 2015 Programme for International Student Assessment (PISA) shows.

The Organisation for Economic Cooperation and Development (OECD) research surveyed about 540,000 students worldwide and uses a points system to rank 72 countries against each other, also looking at countries such as Scotland which are part of larger states.

Davidson's speech follows remarks by the Prime Minister on Friday in which Theresa May said the SNP focus on independence at "the expense of Scottish public services like the NHS and education".

The Scottish Conservative leader will say: "This SNP Government's handling of our education system over the last decade in power has been shameful - and change needs to happen.

"Standards in reading, maths and science are all now getting worse according to an international survey.

"Scotland does not perform above the international average in anything."

Davidson will add: "The Sutton Trust, a leading education charity, last month said this: 'There is no specific area where able children in Scotland really excel.'

"What an absolute disgrace. What a mark of shame. So much for your social justice, Nicola."

The Tories would conduct a "root-and-branch review" of the SNP's flagship Curriculum for Excellence (CfE) school reforms, Davidson will also say.

A spokesperson for Scottish education secretary John Swinney said: "There already has been an independent review of Curriculum for Excellence carried out by the OECD - and not a hand-picked Tory party commission - who considered it to be a bold and a successful reform that was delivering a broadened education experience for young people within Scotland

"The Tories have supported Curriculum for Excellence since its inception - indeed, Liz Smith was right when she said recently that CfE is the way forward for Scotland's schools.

"The PISA results made for uncomfortable reading - but in difficult times, leaders do not abandon their principles, retreat and run for cover. They hold fast to what is right.

"Just as we have seen with her sudden conversion to a hard-right Brexit, Ruth has revealed she cannot be trusted to stand by what she says she believes.

"The Scottish Government will remain firm in our beliefs and listen, not to the turn-and-run Tories but to our international advisers who have told us to be urgent in what we do, but patient about results. We will stay the course."