Pupils who struggle with reading are being made to take a daily “walk of shame” to learn with children who are two years younger than them, an expert has warned.

Professor Sue Ellis, from Strathclyde University, also said schools were pursing an “unethical” policy of splitting pupils into ability groups at the age of five based on unreliable tests carried out when they were in nursery.

Her comments came at a hearing of the Scottish Parliament’s education committee, which is holding an inquiry into the introduction of standardised national assessments.

First Minister Nicola Sturgeon introduced the Scottish Standardised National Assessments (SNSA) as a response to concerns over falling standards of literacy and numeracy and a lack of consistent data across the country.

However, critics claim they are too stressful for the youngest pupils and do not provide useful feedback.

Ms Ellis told MSPs a range of assessments in both nursery and primary were being misused by schools - including a popular literacy scheme which recommended P4 children struggling to read should be sent to P2 classes.

She said: “That daily walk of shame must do terrible things to how children feel about themselves as learners and be detrimental to their health and wellbeing.”

Ms Ellis said children’s progress was so variable when they were young that it was not appropriate to use assessment as a sweeping judgement of progress.

She said: “There are examples in Scotland where local authorities will test children at a particular time and then put the bottom 20 per cent automatically into a fairly rigid, inappropriate for some, set.”

And she said some schools were even setting P1 pupils on the basis of nursery assessments.

“When I explain to them that this enshrines disadvantage and is not an ethical use of data they very often change their policy,” she added.

“There is a very poor understanding at the moment about how an assessment score can predict results.

“I see the introduction of a national assessment as an opportunity to open that up for debate and to get a much better use of assessment, one that actually works for children and parents.”

Ms Ellis said it could take 15 years for the SNSAs to predict accurately children’s future learning.

“So until that point the ethical consideration has to be that you do no harm.

“You don’t set, you don’t stream, you don’t put children into catch-up programmes that remove them from the main body of the class and put them in a different category from other children on the basis of one snapshot.”

Mhairi Shaw, education director for East Renfrewshire Council, told the committee the new Scottish assessments would help teachers.

She said: “They give a measure against a national benchmark and teachers can look at it and see whether children are performing well or not.

“A lot of the profession in East Renfrewshire has welcomed them because it brings back an opportunity to measure their own children’s progress against that national benchmark.”

Following the committee, Joanna Murphy, chairwoman of the National Parent Forum of Scotland, said the practice of "shaming" children was unacceptable.

However, she stressed that groups of children working at different stages and levels, within single or several classes, was common and plays a significant part of the new curriculum.

She said: "We trust the majority of teachers will administer the assessments correctly and act appropriately with the data."

Eileen Prior, executive director of parent organisation Connect, said it was vital young children were made to feel comfortable and confident in their learning from a young age.

She said: “Formal assessment has no place in nursery or P1 when learning through play is the way to encourage children’s confidence in their own learning.

“Children’s progress and development changes all the time at this age and stage, so formal assessment and talk of attainment, tests or streaming are not appropriate for these very young children.

“The priority is for children to make progress and develop a lifelong enthusiasm for, and positive attitude towards, learning.”

Ross Greer, education spokesman for the Scottish Greens, said unethical use of assessments should prompt SNP ministers to end their “bizarre obsession” with testing.

He said: “We need evidence-led rather than headline-grabbing education policies and for the government to start listening to the teachers, parents and experts who have raised concerns.”