Mandarins should stop hiding behind ministers to avoid responsibility for their mistakes She added: "But for ministers to respond by asserting that we are straying beyond our remit is frankly pathetic. And for civil servants to hide behind their ministers will not do. Senior civil servants can be adept as using convention to make detailed scrutiny ineffective. Mrs Hodge, who served as a minister in the Labour Government from 1998 to 2010, said her experience had led her to wonder where power lay in Government. She said: "I more than once wondered whether the power didn't always reside with the permanent civil servants, rather than with the more transient politicians." The committee's behaviour prompted Lord O'Donnell to write to her in December raising concerns about the way the committee was holding departments to account. He was particularly concerned about the way the committee had quizzed HMRC over how it dealt with tax disputes with major companies, particularly Goldman Sachs. She said: "The committee was frustrated. Officials obfuscated, refused to answer our questions. So during one hearing we took the very unusual step of requiring a senior civil servant to give evidence on oath. "Thanks to our pressure, and with the help of a whistleblower, we uncovered serious systemic issues which substantially damaged the taxpayers" interest." Despite the Government announcing changes to the way big tax bills are settled, she said, "mandarins continue to insist that we overstepped the mark." Mrs Hodge said that "the doctrine of ministerial responsibility simply doesn't work across the whole of Government." She cited the example of Helen Ghosh, the former permanent secretary at the Department for the Environment, Fisheries and Rural Affairs for six years, who refused to go in front of the committee to explain the "disastrous" method of paying farmers their European subsidies after she moved to the Home Office. Mrs Hodge said: "She rejected invitations to appear and it was only when I signed an order demanding her appearance that she finally came. In our view, officials who are responsible should remain accountable even if they change jobs. Mrs Hodge added: "It is our job to blow the whistle and shout loudly when the evidence before us is that the executive is not doing a good enough job. That is going to be uncomfortable for both ministers and the civil service. Rather than responding defensively, the civil service should embrace the opportunity. It is in all our interests for this to happen. It will help all of us to deliver better public services with better value. A Defra spokesman said: "Dame Helen Ghosh appeared on a number of occasions before the PAC to discuss RPA issues while she was at Defra and again on 14 November 2011 following her move to the Home Office." Lord O'Donnell could not be reached for comment. Asked about Lord O'Donnell's criticism last month, his successor Sir Jeremy Heywood told MPs: "I cannot speak for Gus and I do not want to go over that old episode... I am certainly not disavowing it, but Gus can speak for himself on that.