Senior civil servant Sue Gray, who conducted the inquiry into the <a href="https://www.thenationalnews.com/world/uk-news/2022/05/25/boris-johnson-and-senior-officials-blamed-for-partygate-failures-in-sue-gray-report/" target="_blank">partygate scandal</a> that contributed to former British prime minister <a href="https://www.thenationalnews.com/world/uk-news/2022/07/07/boris-johnson-will-quit-as-uk-prime-minister/" target="_blank">Boris Johnson</a>'s downfall, has quit the Cabinet Office. She is now poised to become <a href="https://www.thenationalnews.com/tags/labour-party/" target="_blank">Labour</a> leader Keir Starmer's chief of staff, but it is understood that Prime Minister <a href="https://www.thenationalnews.com/tags/rishi-sunak/" target="_blank">Rishi Sunak</a> could, in theory, block the appointment. Mr Sunak’s spokesman told reporters on Friday: “Political impartiality is a fundamental principle of how the civil service works and the Prime Minister is an extremely strong advocate of that.” He declined to say whether the Prime Minister believes Labour’s appointment of Sue Gray undermines the service’s impartiality. A Labour Party spokesman confirmed the proposed appointment. He said: “The Labour Party has offered Sue Gray the role of chief of staff to the Leader of the Opposition.” “We understand she hopes to accept the role subject to the normal procedures. Keir Starmer is delighted she is hoping to join our preparations for government and our mission to build a better Britain”, he added. Conservative Party vice chairman Paul Holmes said Ms Gray's appointment as Mr Starmer's chief of staff should be blocked. “Inappropriate appointment which should be blocked”, he said in a tweet. “Sue Gray's appointment will damage Civil Service relations with political masters. She should take up the position after the next GE [general election].” Jacob Rees-Mogg — a former cabinet minister and close ally of Boris Johnson — called for an inquiry into Ms Gray's contacts with the Labour Party after the announcement. He said her decision to to take a job with Labour “invalidates” her report into lockdown parities in Downing Street and Whitehall. Mr Rees-Mogg said: “It is hard not to feel that she has been rewarded and offered a plum job for effectively destroying a prime minister and creating a coup. This blows apart the idea of civil service impartiality.” He added: “We should have an inquiry into what she has done in her contact with Labour while she's been a civil servant, particularly those with the office of the Leader of the Opposition. Her report is discredited along with the testimony that was collated by her. That's why there must be a proper inquiry.” Nadine Dorries, who served as Mr Johnson's culture secretary, described the Gray report as a “stitch-up” and said the reported move to Mr Starmer's office was “not surprising”. Conservative MP Brendan Clarke-Smith said he was “genuinely shocked” and accused Mr Starmer of having “scant regard for the public image of the civil service and the damage this will do”. He added: “After the events of last year, people will quite understandably be questioning the appropriateness of this appointment, including issues of impartiality.” Tony Blair's former chief of staff welcomed the move to appoint Ms Gray to that position. Jonathan Powell, who left the diplomatic service to work for Mr Blair, said it was “another sign that Labour is ready to take over the reins of power from an exhausted and fractured Conservative Party”. Amid speculation about the move to block the appointment, the Prime Minister's spokesman outlined the Acoba process to reporters. “Acoba will consider the information provided”, the spokesman said. “They'll make necessary requests for information, they'll consider it, they'll come to review what should be applied to the appointment under the government's business appointment rules, and they will provide a provisional recommendation and then the applicant is asked to confirm if they're content to abide by the provisional advice. “And then, obviously, the recommendations are then made to the relevant department or minister, depending on who they are.” A senior civil servant in the UK, Ms Gray led an investigation into alleged <a href="https://www.thenationalnews.com/tags/covid/" target="_blank">Covid-19</a> lockdown breaches by government officials, including Mr Johnson and his wife Carrie. Her report on the incidents — which received significant media attention — was published in May 2022. Her reviews of senior cabinet ministerial behaviour have led to high-profile sackings and resignations, including Damian Green, a close ally of former prime minister Theresa May, and Andrew Mitchell, the former chief whip. Some critics have suggested that Ms Gray has been influential in blocking freedom of information requests, but others have praised her for her impartiality and rigour. Ms Gray served as the secretary of the Department of Finance in <a href="https://www.thenationalnews.com/tags/northern-ireland/" target="_blank">Northern Ireland</a> from 2018 to 2021. Before that, she worked as the head of ethics in the Cabinet Office, where she oversaw reshuffles and honours lists. She is often described as an elusive character and some politicians have gone so far as to suggest that she is the “real leader” of the UK.