Widespread appeals have been lodged over the national test results for 14-year-olds which appear to show that pupils were being marked far lower in English than in other subjects.
Exams advisers are now facing criticism over their marks, awarded when the papers were sent to external markers for the first time. Some schools say the scores seem to suggest that pupils are two years behind where they should be.
Last night, it was feared that all the 625,000 pupils who took the tests this year could have been marked too low. It is not clear whether wholesale adjustments could be made before parents are told the marks at the end of the summer term.
Exam boards are likely to raise the issue today at a meeting with government advisers. They say they marked the tests as instructed and that if there is a problem it must be solved by the School Curriculum and Assessment Authority (SCAA), which oversees the tests.
Professional examiners were brought in to mark the national curriculum test papers after teachers' complaints about the extra work that they involved led to a two-year boycott in 1993 and 1994. Those schools which did the tests in the first two years after their introduction marked the papers themselves but had the results externally validated.
The National Association for the Teaching of English, which represents English teachers, had dozens of calls from distraught heads of department on Thursday and Friday after some of the marked papers were sent back to schools for checking. It expected more complaints early this week: all papers are due to be sent back by tomorrow.
Anne Barnes, general secretary of the association, said SCAA should take immediate action to calm schools' fears. At the very least it should waive the pounds 5 per pupil fee for appeals. The SCAA said it had only received about 20 calls from schools.
Its chief executive, Nick Tate, said: "The mark schemes have been extensively trialled. Markers have been trained to ensure that they apply the mark scheme fairly and consistently. Where schools are unhappy there are clear procedures for appeal."
The following are some sample questions from test papers.
1. Write about an incident in which you had to leave a place you knew well.
2. Read Brutus' and Antony's addresses to the crowd from Julius Caesar and say what you learn about the differences between them. Do you think Brutus and Antony seem to be people whom the Romans can trust?
3. Read a letter from the Red Cross appealing for money for war victims in Eastern Europe. Say in what ways it tries to persuade people to send money, commenting on the language, the layout and the impressions you are given of the Red Cross.