A head teacher has resigned following allegations some pupils' SATS papers were tampered with, Rotherham Borough Council has confirmed.
Some of the Key Stage 2 maths test results are under scrutiny
Pam Ward, the head teacher of Kilnhurst Primary School in the town left her post at the end of the last term.
A council statement said the National Assessment Agency had conducted a full investigation into the concerns.
As soon as the inquiry results are known parents of the children affected will be contacted.
Ms Ward was praised by Ofsted inspectors for raising standards at the school since she took over in 2001.
But she offered her resignation after the independent investigation was opened into concerns raised by the external marking agency about Key Stage 2 maths tests taken by pupils.
Catharine Kinsella, Head of School Improvement for Rotherham Borough Council said in a statement : "The National Assessment Agency has conducted a full and impartial investigation into concerns on whether some of the scripts represented the children's independent and unaided work.
"It is highly regrettable that both pupils and parents of Kilnhurst Primary School could be experiencing anxiety over this situation but the LEA is working closely with the school governors and the acting head teacher to resolve the issue.
"The school has notified all those parents who may be directly affected and as soon as the outcome of the national Assessment Agency inquiry is known, all parents of pupils at the school will be fully informed."
She said Rotherham Local Education Authority had tried to minimise the impact on the former Year 6 pupils concerned.
She said: "Fortunately, SAT test results are only one source of information on which secondary schools base levels of achievement and we believe no pupil has been disadvantaged by the delay in the mathematics results."
The National Assessment Agency confirmed they were investigating the test results from the school.