A Conservative former minister has defended the “integrity” of Sue Gray, the senior civil servant who led the inquiry into the Partygate scandal, after her appointment to Labour’s staff. Conservative MPs have expressed outrage over the planned recruitment of Gray, who received national prominence for her role investigating lockdown-breaking parties in Downing Street. It has been leapt on by Boris Johnson and allies as part of attempts to discredit the privileges committee inquiry into whether the former prime minister lied to the House of Commons over lockdown breaches. But on Saturday Gray received backing from a former Conservative Cabinet Office minister, Francis Maude, who said he never had the “slightest reason to question either her integrity or her political impartiality”. In a letter to the Times, the Conservative peer said Gray, who worked as his principal private secretary for a period of time, was not the first civil servant to move to a political role and would not be the last. “We should be as relaxed about this as we should be about people who have had previous political involvement coming into the civil service,” he said. “Regardless of any political background or leaning, civil servants must of course comply with the civil service obligation of impartiality while they are in post. “Our civil servants should have brains, knowledge, judgment and strength of character to give robust advice to ministers. Gray has all these qualities in abundance; Starmer is fortunate to have secured her services.” In a letter to the same newspaper Bob Kerslake, the former head of the civil service, said accusations of impropriety over the proposed move were “wide of the mark”. He wrote: “The role is as much an organising one as a political one and it is no surprise that two previous chiefs of staff, Jonathan Powell and Ed Llewellyn, were drawn from the diplomatic service.” He said Gray had been asked by the Labour leader, Keir Starmer, because of her “experience and undoubted abilities”, adding: “I hope the appointment process moves quickly and she is able to take up her new role.” Starmer has so far dodged questions about when conversations began with Gray, who is expected to await the decision of the Advisory Committee on Business Appointments (Acoba) before starting the role. Parliament’s anti-corruption watchdog can advise waiting periods before civil servants take on other jobs and the prime minister ultimately makes the final decision. On Saturday, the Labour chair, Anneliese Dodds, rejected the suggestion the move was a “distraction” from the privileges committee inquiry as she insisted that all necessary procedures would be followed. “Sue Gray is a person of enormous integrity. Someone who served in the civil service under ministers of a number of parties actually, someone who’s always served with that integrity,” she told Sky News. “I’m really delighted she’s joining the Labour team at that point where we’re readying ourselves for government if the British public backs us at the next general election. “What’s important to us as Labour, as ever, is that we see the same rules and approaches being applied to this, as she would see with any other appointment. That’s why the civil service procedures on confidentiality will be followed. “It’s why the civil service watchdog Acoba will need to look at this, just as it would with any other appointment, and it’s quite right those procedures will be followed. They will be for Sue Gray, just as they would be for any other senior civil servant.”