Ministers should seriously consider abolishing the beleaguered exams regulator Ofqual so ministers have direct accountability, the chair of a powerful committee of MPs has said. Robert Halfon, the Conservative chair of the education select committee, said the Office of Qualifications and Examinations Regulation was no longer fit for purpose, but also that there were still significant questions over the way ministers handled the grades crisis, which led to a humiliating government U-turn. “It is worth considering abolishing Ofqual in its current form, it is not fit for purpose, and bringing it back within the Department for Education. Ministers should have proper control and accountability,” he told the Guardian. On Monday the government announced it would allow A-level and GCSE pupils to use grades awarded by teachers, after the computer moderation process downgraded marks, leading to some pupils missing out on university places. The committee warned in July that “Ofqual’s standardisation model aims to adjust grades to ensure they are broadly in line with previous years … there are concerns about risks of using historic data, which might not be fair for … schools which are on an upward trajectory.” However, the under fire education secretary, Gavin Williamson, told Sky News on Tuesday problems had only “become apparent … when we were seeing the results directly coming out.” Halfon, a former education minister who has been deeply critical of the government and Ofqual’s handling of the crisis, said there needed to be full transparency of the correspondence between the department and Ofqual to see when concerns were raised. “All the minutes and internal documents between Ofqual and the DfE now need to be published to find out what’s gone on, how much this has cost the taxpayer and what questions were asked by the department and what actions were taken by Ofqual to ensure a level playing field for all students,” he said. Halfon said both ministers and Ofqual bore responsibility for the string of changes and U-turns made in the days shortly before and after results were announced, sending students, parents, teachers and universities into turmoil. “Why was the appeals system not set up properly with a much wider base for appeal from the beginning, as recommended by the education select committee? “We could have had appeals allowed simply and quickly with retired teachers, Ofsted inspectors examining them – so from day one appeals could have been turned around in a few weeks. But that never happened and it was only announced the day before that appeals could be made on the basis of mocks. And then only on Saturday the decision on not paying for appeals – why wasn’t this all decided in advance?” Williamson refused to personally back the head of Ofqual, Sally Collier, on Tuesday, saying only that Collier – who has not spoken publicly since students’ results were published last Thursday – had worked hard in her position as head of the exams regulator. Williamson is facing significant criticism over his own role in the results chaos. The Liberal Democrats have called on Boris Johnson to sack his education secretary, criticising attempts to pass the blame on to Ofqual. In a letter to the prime minister, the party’s education spokeswoman, Layla Moran, said the government’s failure to take responsibility risks further eroding public trust in the exams system. “There must be consequences for this catastrophic failure of governance. Gavin Williamson must resign, and if he refuses to go Boris Johnson must sack him,” she said.