Education union Voice has called for an independent inquiry into "government meddling" in the exams system.
The union said the qualifications system "is in danger of disintegrating under the strain of competing tensions" after the controversy into GCSE marking.
"There are major concerns about the effects of interference and threats from the Westminster government," a Voice spokesman said.
"Such political interference has little to do with education and belittles the enormous efforts being made by students and their teachers to achieve ever more stringent standards.
"The GCSE has been enormously successful in enabling the vast majority of students to register achievements within the range of their capabilities. The exam boards had been leant on to be stricter, particularly with GCSE English."
The spokesman added: "Students are in a very difficult situation. Many of them achieved consistent grades across other subjects but dropped down in English, which will blight their lives."
The Association of School and College Leaders has claimed that 143 schools in England missed their GSCE targets as a result of the English Langauge grades.