A second primary school is being investigated by the Department for Education over allegations about its handling of Sats exams, following a probe into a school led by the same headteacher.

The Croydon Guardian understands staff at Selsdon Primary, in Addington Road, are accused of helping Year 6 pupils during tests to boost their grades.

The department's Standards and Testing Agency is already investigating Heavers Farm Primary in South Norwood over concerns about its exams and has withheld the results of last year's Sats.

Both Heavers Farm and Selsdon are led by executive headteacher Susan Papas, who this week insisted there was no evidence of wrongdoing.

The DfE received reports this week from a former Selsdon Primary pupil's mother, who claims Year 6 children were tipped-off when they had written incorrect answers and been given longer than allowed to complete papers.

It is believed a former teacher at the school has reported similar allegations.

The parent who reported Selsdon to the DfE, who did not want to be named to protect her child's anonymity, told the Croydon Guardian her son had been alerted to wrong answers by a teacher.

She said: "He came home and said, 'Mummy, it was really good, really easy.' I felt really proud of him. But then he said they were really helpful, and I said 'What do you mean, helpful?' He said, 'Oh, they come round, look over your shoulder, tell you where you've gone wrong. I was like, sorry?

"I questioned him a bit more and he said he was doing his work and a teacher leant over his shoulder and looked at him to say 'Look again, check what you've written'. He looked up at her, rubbed the line and did a different one, and she sort of said 'check again' until he did the right answer."

Ms Papas has been headteacher of Heavers Farm since 2008 and was appointed executive head of Selsdon in September last year.

The Croydon Guardian contacted her office several times this morning to allow her to respond to the allegations but was told that she was not available for comment.

Earlier this week she said she was "shocked" by allegations about Heavers Farm’s Sats and stressed she had been at Selsdon Primary when exams were sat.

She added: "I've completed co-operated with the local authority and the STA (Standards and Testing Agency) and have been working with them to resolve very quickly. Something happened when I wasn't at the [Heavers Farm] school. I am co-operating to sort it out as soon as possible.

"We've been regularly moderated by the local authority and there has never been a whiff of anything before, and nor should there be."

Asked why the allegations could have been made, she added: "There have been a number of staff who have left under a cloud for various reasons and I would not be surprised if they were quite malicious. There is no evidence for it."

A DfE spokeswoman said: "We have recently been made aware of allegations of maladministration at Selsdon Primary. We take all allegations very seriously and are currently investigating."

Croydon Council said on Tuesday it was not aware of any concerns about Selsdon Primary.

A council spokesman said today: "The Standards and Testing Agency contacted us yesterday on this matter and we are assisting them with their investigation at the school. The agency will make a decision on any action to take once this investigation is complete."

Are you a teacher or former teacher at Heavers Farm or Selsdon Primary? Has your child taken Sats exams at either school? Call 020 8722 6351 or email chris.baynes@london.newsquest.co.uk