British Prime Minister Gordon Brown shook up his Cabinet on Friday in hopes of hanging on to his job in the midst of a scandal over lawmakers' expenses, a string of top-level resignations and catastrophic results expected in local elections.

Brown promoted key allies to his inner circle as he tried to crush efforts to oust him within his Labour Party. Some legislators view Brown as the key obstacle to the party's hopes of avoiding defeat in the next national election, which must be held by June 2010.

Work and Pensions Secretary James Purnell, a 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, who was regarded as one of the Cabinet's best performers, announced Friday he was quitting his post — the sixth surprise resignation in four days. But he offered Brown his support — mitigating the impact of his departure.

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.

Though Brown has gained praise overseas for his handling of the global economic crisis, he trails the main opposition Conservative Party in opinion polls and is widely expected to lose the next national election.

His government has suffered the most in a scandal over lawmakers' expense claims, blamed for failing to reform a system that allowed legislators from all parties to charge for items like horse manure, porn movies and repairs to the moat of a country mansion.

Early results from local elections held Thursday showed Brown's Labour losing scores of seats to the Conservatives and Liberal Democrats.

Alan Johnson, the affable health secretary — who is often mentioned as a replacement for Brown — urged colleagues to unite behind him despite the 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.

Treasury chief Alistair Darling was not expected to be moved from his 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.

Darling "has faced a lot of criticism, but we think he has actually done a reasonable job given the very trying circumstances," said IHS Global Insight chief economist Howard Archer.

Alan Sugar, a brash businessman and host of the British version of "The Apprentice" television show, was likely to be made a member of the House of Lords to allow Brown to hand him a roving role to promote entrepreneurship and help stimulate Britain's economy.

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 now 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.