The letter from the Joint Council for Qualifications, which represents Britain’s major exam boards, said: “The original timescale could only be achieved if we now compromise the quality of development in the areas of assessment and standards,” the letter said. “We urge you in the strongest terms to defer implementation.” Despite the letter, the Department for Children, Schools and Families is pushing ahead with the “fourth phase” of diplomas. There will be nine in total, with courses below GCSE and at GCSE and A level-standard in humanities, languages and science. Only the advanced level science diploma will be held back for a year.