Labour is pushing for the head of Medway education to make a grovelling public apology at next week’s council meeting after an embarrassing administrative error over the Medway Test.

Thousands of parents received their results last week and many were immediately baffled after being told their child had failed but realising the scores did not add up.

Medway Council accepted its mistake in a statement on Monday saying that the overall mark and pass/fail result was correct. It affected a total of 1,300 schoolchildren, all of whom had failed.

Cllr Andrew Mackness, who has recently taken over the cabinet brief following the death of Cllr Mike O’Brien, admitted it was embarrassing and said “sorry”.

But the Labour group has called for a further apology in front of councillors next Thursday. They said the affair had left children and their families “confused, distressed and panicked”.

Cllr Adam Price, its education spokesman, said: “The time of the 11-plus is a stressful and worrying one for children and their families anyway. This debacle caused great distress for over 1,300 Medway pupils and their families and that is simply unacceptable.

“Cllr Mackness has blamed an ‘administrative error’ but that will not comfort the families who feel that they have been badly let down by the council. It is only right that Cllr Mackness apologises to those families and for the distress that has been caused.

“It’s important that Cllr Mackness is clear about what lessons have been learned so that he can begin to restore trust in the council.”

Cllr Andrew Mackness said he was made aware of the problem on Saturday as soon as a parent raised the issue.

He said: “It’s unfortunate, it’s not something I’m very happy about, it won’t happen again. I’m sorry about the distress that has been caused.”

“It was an administrative error from a mail merge that should have been checked and was in one case and not the other. The error has been identified.”

He explained that the information was drawn from a data sheet and the results for the extended writing score had been drawn from the wrong column.

"I’m sorry about the distress that has been caused"

Cllr Andrew Mackness

There is just a two week gap between the test and the results being posted, but Cllr Mackness said he did not think officers were rushed.

“We’ve always tried to provide a prompt response to parents and children following the Medway Test,” he said.

“What I’ve asked officers for the future is that we don’t rush.

"f there is a need to add in an extra checking mechanism next year, then we will do so.

"If that means results will be sent out on a Monday as opposed to a Friday then that’s something I will consider.”

The results of the test were emailed or posted last Friday, with Year 6 pupils needing to score 513 to pass and go on to grammar school.

But for 1,300, their overall score did not match the total of the individual scores listed – which could have made the difference between a pass and a fail.

The scores for maths and creative writing should have been doubled and added to the verbal reasoning score.

A council statement issued on Monday said: “We have thoroughly rechecked the results and we will be reissuing result letters to those families affected with the correct figures, but this will not impact the total score or the assessment outcome for pupils.”

The deadline for review requests has been extended to 10am on Monday to give parents more time to prepare.

Lydia Smith, of Rochester, mother to 10-year-old twins Naomi and Frankie, said: “My son passed but my daughter did not, which was quite upsetting.

“The next day we found out there may have been an error. It’s been very badly handled. I understand what’s happened but it doesn’t give you much faith in the whole process.”

More than 3,000 children sat the Medway Test in September. A total of 23% will be selected for grammars with another 2% chosen on appeal.