National test results for primary school pupils have been delivered amid fears that as many as one in five marks could be inaccurate and will have to be sent back for review.

Edexcel, the private company, was brought in to mark the tests, previously known as SATs, after last year’s disaster when 1.2 million results were delayed by more than a month.

It was forced to omit some quality control checks to stay on target after hundreds of markers were unfairly disqualified because of a flawed vetting procedure.

Ian Foster, from the National Association of Head Teachers, said that there was particular concern about the accuracy of marking of English papers this year.

“Heads are worried that the mark scheme hasn’t been applied correctly and there are issues surrounding what schools consider inaccurate or unjust marking,” he said.

The process for review was cumbersome and schools must send in their appeals by the end of next week if they are to be cons

A small number of schools have results outstanding, the Qualifications and Curriculum Authority (QCA) said, but 99.9 per cent of 11-year-olds will find out today how they did in the tests in English, maths and science, which they took in May.

Ministers had insisted that Edexcel return 99.7 per cent of results by today.

Andrew Hall, acting chief executive of the QCA, said: “The successful delivery of over 1.7 million results in three subjects, all marked during a six-week window, has been the result of close teamworking and a commitment to ensuring accurate and timely information is available on each child’s achievements at the end of their primary education.”

The QCA and Edexcel were under extreme pressure to meet the deadline following the collapse of the system last year after which Ed Balls, the Schools Secretary, abolished the tests for 14-year-olds.

Science tests will be dropped next year but unions have threatened to ballot their members about boycotting the tests for 11-year-olds if they are not completely scrapped.

More than a million school children had to wait more than a month for their results last July after the contractor, ETS Europe, suffered problems with its computerised system.

The American company’s contract was later cancelled and Edexcel, which had held the contract previously, took over.

An independent inquiry into the delays blamed the QCA for failing to manage the contract properly and ETS for a lack of planning and not having the capacity to deliver the contract on time.

The National Union of Teachers and the National Association of Head Teachers, said that, based on previous experience, they still had concerns about the quality of marking.

Kathleen Tattersall, chair of the exams watchdog Ofqual, said she would be monitoring this year’s results to ensure that they were fair. “Following the problems experienced last year, the timely delivery of results will be welcomed by schools, parents and pupils,” she said.

“As regulator, Ofqual is continuing to monitor the quality control of the marking of this year’s papers, and we will be listening to schools about any concerns that they might have.

“Building on research already done by QCA, we will do some further work into the marking quality of this year’s tests with the aim of reporting later this year.”

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