The warning comes as the Scottish Liberal Democrats accused the SNP/Green Government of choosing to “plough ahead” with testing at P1 despite internal opposition from both parties and a parliamentary motion in 2018.
The Government claimed there was “no evidence” testing at P1 stage negatively impacts mental health among children.
At the SNP’s national conference in Aberdeen last month, the party backed plans for an increase in the school starting age and the introduction of a kindergarten stage for three to six-year-olds.
But the SNP’s policy chief, Toni Giugliano, also called for an end to testing at P1 due to the increased pressure on young children and the impact it may have on their mental health.
Despite this, the Government defended its approach to testing at P1 and told former Scottish Liberal Democrats leader Willie Rennie in an answer to a written parliamentary question there are “no plans to discontinue national standardised assessments for P1 learners”.
Sue Palmer, a former primary headteacher in the Borders and campaigner for the increase of the school starting age, said appropriate teaching for young children would be impossible if the Government continues to insist on standardised assessment at P1.
Palmer, who has written several books on the challenges for children’s development in the modern world and sparked the Upstart Scotland campaign, told Scotland on Sunday there were three “huge” issues facing Scottish education.
These are the poverty-related attainment gap, the “ever-increasing additional support needs”, and an “alarming escalation” of mental health problems among children.
She said: “All could be ameliorated by introducing a developmentally-appropriate kindergarten stage ‘til children are at least six.
“As long as the Government insists on standardised assessment of literacy and numeracy when children are five, local authorities will continue to demand evidence of progress in these subjects at P1, and developmentally-appropriate teaching will be impossible.
“A great many children are simply not ready for formal teaching of the three Rs at five years old. We need an educational culture change in early years.”
Rennie, Scottish Lib Dems education spokesperson, said the Government’s plans to continue P1 testing “ignores the voices of parents, teachers, parliament, and even their party’s own policy convenor”.
He said: “The unequivocal message from teachers has been and continues to be that these pointless tests tell them nothing that they do not know already. It is an utter waste of time and a dangerous blockade that gets in the way of learning for more than 40,000 children every year.
“In ignoring the will of Parliament, the SNP are behaving in a profoundly undemocratic way. They seem to only want the Scottish Parliament to be a talking shop for independence.
"They don’t like accountability, transparency or doing what is best for our children. The education secretary is delusional if she thinks these tests are helping.
“Once upon a time that wasn't just the view of teachers and the Scottish Liberal Democrats, it was the Greens too. Now it seems they have folded and are part of a Government that intends to carry on these tests.”
A Scottish Government spokesperson said: “David Reedy’s independent review of Scottish National Standardised Assessments (SNSAs) for P1 in 2019 found that they have significant potential and should continue. His recommendations on enhancing assessments and support materials for teachers have since been implemented.
“The assessment approach in Scotland places teacher professional judgement at the heart of the process. SNSAs are a helpful additional source of information for teachers when considering children’s progress in literacy and numeracy.
"Our survey of staff using the assessments in 2021/22 showed that the majority found the assessments helpful in informing future teaching and learning.
“There is no evidence of the assessments having a negative impact on the health and wellbeing of children and young people.”
The debate has been fuelled as the Government braces for impending teacher strikes, with members of the Educational Institute of Scotland (EIS) – the country’s biggest teaching union – due to walk out on November 24.
The industrial action could shut up to 2,000 schools across Scotland, with further strike dates mooted.
Education secretary Shirley-Anne Somerville has said the Government is “absolutely determined” to find alternative funding for the teacher pay deal. The union rejected a 5 per cent pay increase in September.