U.K. Prime Minister Keir Starmer has replaced his top aide and the Treasury has acknowledged that key tax-raising plans were under review as the Labour government tried to correct course from what even allies say has been a rocky three months in power.

In an attempt to end the turbulence engulfing Britain’s first Labour administration in 14 years, the prime minister on Sunday moved his chief of staff, Sue Gray, out of her role following internal complaints about the political operation she ran at 10 Downing Street.

The dramatic move came as doubts hung over Labour’s fiscal plans just three weeks before a make-or-break budget, with officials admitting they were examining three tax proposals amid concerns that they were either unworkable in their current form or would end up costing rather than generating money. The developments reinforced a sense that Starmer and his team are struggling to make the transition from opposition to government.