Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. A GCSE English examiner has warned that marking guidance is so poor that students face being given the wrong grades in the subject.They claimed that fellow examiners for the exam board AQA were left “shocked” and “horrified” by the scripts chosen as guides for marking.In a series of now deleted messages on Twitter, the anonymous examiner alleged that “the standardisation scripts are all over the place” for this year’s English language GCSE.AQA cautioned that these were “personal opinions” adding that they do not “reflect the overall picture”.But the examiner’s claims will add to students’ fears that they will be left disappointed with their results in August. The whistle-blowing examiner said that there was “no debate at pre-standardisation among the senior examiners”.They added: “That means that the meeting where the standard is evaluated and agreed was a farce. We had examiners horrified at the standard.”Problems in the standards were flagged by the number of markers failing to spot elements supposed to ensure consistent standards.In one, the pupil was given 14 out of 40 when the “correct” score should have been 21, and in another a pupil was awarded 26 marks when a more senior examiner deemed the “correct” mark to be 40.They told the Times Education Supplement magazine that some examiners were so unhappy with this year’s standardisation materials they used those for 2018 instead.Claire Thomson, AQA’s director of operations, said: “These personal opinions, which the user has now deleted, don’t reflect the overall picture.“Getting students the results they deserve is our top priority and we have very effective quality assurance measures in place to make sure examiners mark to a high standard.”Ofqual, the exams watchdog, uses a system called “comparable outcomes” to ensure that roughly the same proportion of pupils get similar grades each year, and those who are the first to take the new, reformed courses are not at a disadvantage compared to other cohorts. This summer is the second year that students are taking revamped GCSEs in a raft of subjects, and the third year of the new English literature, English language and maths exams.The new courses were part of a package of reforms by Michael Gove, the former education secretary, designed to toughen up syllabuses, make courses more linear, and cut down on the number of students getting A*s.Last month, the head of exams watchdog warned schools to be braced for “more variation than usual” in this year’s GCSE and A-level results, as reforms take their toll.