British Prime Minister Gordon Brown began a shakeup of his ministerial team Friday, as he attempted to recover from a scandal over lawmakers' expenses, a string of high-profile resignations and poor election results that have seriously weakened his authority. Brown was likely to promote key allies as he sought to head off attempts to oust him by critics within the ranks of his Labour Party. Some legislators view Brown as an obstacle to the party's hopes of avoiding defeat in the next national election, which must be held by mid-2010. Work and Pensions Secretary James Purnell, as 39-year-old fast rising star in Brown's government, dramatically quit late Thursday and urged Brown to step aside. "I now believe your continued leadership makes a Conservative victory more, not less likely," he told Brown in a resignation letter. Defense Secretary John Hutton - regarded as one of the Cabinet's best performers - announced Friday he was quitting his post in the sixth surprise resignation in four days. Britain's defense ministry confirmed in a statement posted on the Internet that Hutton had quit. Hutton's office did not immediately respond to requests for comment. Brown's office confirmed that a reshuffle of the Cabinet was under way - the first since October - but said that ministers' new roles would not be immediately announced. Britain's BBC and Sky News reported that Treasury chief Alistair Darling would not be moved from his key role handling the economy, despite concern over his expenses claims. Darling has repaid some money after he acknowledged mistakes in his claims and has faced criticism over his manipulation of the housing allowance system. Brown replaced Tony Blair in June 2007. He has gained praise overseas for his handling of the global economic crisis, but seen his domestic approval ratings tumble. His government has been hammered by weeks of leaked details about lawmakers' expense claims, which have fueled public anger at politicians. Early results from local authority elections held on Thursday showed Brown's Labour losing seats to the Conservatives and Liberal Democrats, as voter chose to punish the British leader over the scandal. Alan Johnson, the affable current Health Secretary who's tipped as the likeliest replacement for Brown, urged colleagues to unite behind their leader in the wake of likely poor election results. "I continue to believe that Gordon Brown is the best man for the job," Johnson said in a statement. "It is vital now, more than ever, that we unite for the sake of the party and the government." Johnson was expected to be appointed Home Secretary as a reward for his loyalty. His office declined to immediately comment on media reports that he would be placed in charge of the law and order ministry. Brown was expected to promote Children, Schools and Families Secretary Ed Balls, a longtime ally and former adviser, and Yvette Cooper, Darling's deputy at the Treasury and Balls' wife. Current Home Secretary Jacqui Smith, Communities Secretary Hazel Blears, Purnell and two junior ministers have quit amid the expenses scandal. Blears and Purnell expressed doubts over Brown's ability to restore public trust in politics. Restive rank and file legislators have mulled collecting signatures to an e-mail statement calling on Brown to resign, but have yet to make their campaign public. International development secretary Douglas Alexander said that lawmakers must decide whether they will no pledge loyalty to Brown and back his new ministerial team. Legislators "have a serious judgment to make in the hours ahead and it's silly to pretend they don't," Alexander told BBC radio. "There are some within our parliamentary party who honestly and sincerely believe that the right course is for the prime minister to stand down, that's not the position I believe is the mainstream position," he said. Opposition leader David Cameron said the government was falling apart. "With this resignation, the argument for a general election has gone from being strong and powerful to completely unanswerable," he said.