The education secretary, Gavin Williamson, has lost the trust of his officials to such an extent that he can no longer serve effectively in the cabinet, one of the most senior Tory MPs said last night as pressure grew on Boris Johnson to sack him. Sir Bernard Jenkin, who chairs the powerful Commons liaison committee, which will grill the prime minister on 16 September, told the Observer that after Williamson’s humiliating U-turn over A-level and GCSE results, the secretary of state made a bad situation worse and caused a “complete breakdown” of trust in his department by seeking to blame officials for the crisis. With Tory anger over the episode at boiling point, another of the most senior and influential Conservatives on the backbenches said he would be “amazed” if Williamson survived for long, and that his reputation in the education world had been “irreparably damaged”. Williamson’s fate is expected to be discussed by the executive of the backbench 1922 committee of Tory MPs when parliament returns from the summer break on 1 September. So far Boris Johnson, who is expected to return from a holiday in Scotland this week, has said nothing publicly about the crisis. He has stood by Williamson after the education secretary at first defended the use of a controversial algorithm which led to huge numbers of A-level students receiving lower than expected grades, then ditched it altogether for both A-level and GCSE assessment. While the Guardian had reported that Ofqual’s algorithm would downgrade 39% of grades recommended by teachers, the scale of the disaster became apparent when results were issued and students reported bizarre and inexplicable results. The U-turn came after days of confusion and distress for millions of pupils, parents and teachers. While the climbdown came as a relief to many pupils, it unleashed fresh chaos across the education sector as universities and colleges were faced with more students who had gained the required grades than the number of places they could offer. Jenkin suggested that the implications of Williamson’s behaviour in blaming officials rather than taking the blame himself were serious for the wider working of government, and should not to be ignored. Williamson did apologise and eventually gave his backing to Ofqual but only after clear efforts had been made to shift blame on to others. Jenkin said: “The deal between ministers and officials is that officials give their best advice and ministers get to make decisions. This means that when something goes wrong ministers take the blame, and that is the reason why officials will be free to speak and give the best advice. But if officials feel they are going to be blamed in public they will not give the best advice to ministers. “In the Gavin Williamson case there has been briefing against the permanent secretary (at the Department for Education) and Ofqual. This is not likely to engage enthusiastic co-operation from the department and it permanently disables Gavin Williamson as secretary of state because there will have been a complete breakdown of trust.” The Williamson episode has fuelled a growing sense of resentment among many Tory MPs who feel their views are being ignored by a centralised operation run from No 10, and that ministers and officials with previous records of backing Johnson both in the Brexit referendum, and in his campaign for the leadership, are being protected however badly they perform. Another former minister said: “There are so many capable people on the backbenches, yet we hang on to Gavin Williamson. Look at Greg Clark and Jeremy Hunt. The parliamentary party is split. If you backed Vote Leave and backed Boris for leader, you are protected. The rest of us are not listened to. In fact, we are completely ignored.” Tory unrest over Williamson’s position has added to pre-existing frustration over why he held the education post in the first place, having never shown a particular interest in the issue. The cabinet post came as a reward for his help in ensuring Johnson secured enough MPs’ support to win the leadership. One Tory minister said that Williamson’s survival was “shocking”, before adding wearily: “But nothing surprises me.” Williamson has also been protected by the reluctance of Mark Spencer, the chief whip, to back a reshuffle, concluding that it could leave Johnson with more enemies than new friends. The positions of both Williamson and Ofqual officials will again be in the spotlight when parliament returns. Both will face a grilling by MPs on the education select committee, which is led by Robert Halfon, the independent-minded Tory MP who has been hugely critical of the exams fiasco. Whitehall insiders said that there was already a scramble taking place to examine notes, memos and emails, to decipher who knew what, and when.