A "publication error" has been blamed for leaving more than a thousand parents confused about their children's 11-plus results.

The results of the all-important Medway Test were emailed or posted on Friday, with Year 6 pupils needing to score 513 to pass and go on to grammar school. But for 1,300 pupils their overall score did not match the total of the individual scores listed – which could make the difference between a pass and a fail.

Medway Council has today apologised for the error which saw the wrong extended writing score printed, and said the total score is correct for all candidates. The problem only affected pupils who had not passed.

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A Medway Council spokesperson said: "The total score and assessment outcomes published in Medway Test result letters is correct for all candidates, despite a publication error which led to the wrong extended writing score being printed in the letters to non-selective (non-grammar) pupils.

"We worked as a matter of urgency to look into the Medway Test results after a figure was incorrectly published on non-selective (non-grammar) result letters. While individual scores published for maths, verbal reasoning and extended writing papers did not add up to the total score, the total score stated and the assessment outcome in the results letter is correct.

"We have thoroughly rechecked the results and we will be re-issuing result letters today 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, 10 October, to give parents more time to prepare in acknowledgement of any uncertainty this has caused over the weekend.

"We are sorry for the concern and confusion this may have caused parents at what is a very important time in their child's education.

"Parents who would like further clarification on their child’s results can contact their school directly."

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

Anxious parents contacted tuition centres and education adviser Peter Read over the weekend.

One worried mum posted online: “My daughter’s score is wrong. If the individual scores are right then she passed. If not, she failed.”

Another said: “My son’s scores add up correctly. His twin sister’s do not. He passed, she did not. Been a lot of tears in this house and I will be furious if Medway Council have mucked this up.”

One mum commented that there is a 50-mark discrepancy in her daughter’s results.

She said: “She was told yesterday she had failed Medway test. Now that I have added up her test scores she is over the pass mark comfortably. She is hoping she has now passed. I’m trying to tell her original decision stands as I’m worried she is going to have to face the disappointment again.”

Has your child been affected? Let us know in the newsroom on 01634 227803.