British Prime Minister Liz Truss on Wednesday ruled out a windfall tax on oil companies to pay for her plans to tackle the energy crisis. Speaking during her first session of prime minister's questions in the House of Commons, Truss rebuffed opposition calls for a new windfall tax, even as she refrained from explaining how she would fund a plan meant to help the public pay energy bills skyrocketing because of Russia's invasion of Ukraine. The plan is expected to be delivered on Thursday. “I am against a windfall tax,'' she said. "I believe it is the wrong thing to be putting companies off, investing in the United Kingdom just when we need to be growing the economy.” Read:New UK PM Truss vows to tackle energy crisis, ailing economy Earlier Wednesday, Truss held her first Cabinet meeting, appointing a government diverse in race and gender and united in its support for the new leader’s staunchly free-market views. Truss, 47, was appointed prime minister by Queen Elizabeth II on Tuesday after winning an internal election to lead the governing Conservative Party. She immediately put her stamp on the government, clearing out many ministers from the administration of former Prime Minister Boris Johnson — notably those who had backed her leadership rival, Rishi Sunak. She made Kwasi Kwarteng her Treasury chief, a key role for a Cabinet whose inbox is dominated by the energy crisis triggered by Russia’s invasion of Ukraine, which threatens to push energy bills to unaffordable levels, shuttering businesses and leaving the nation’s poorest people shivering at home this winter. Kwarteng is the first Black holder of the job, formally titled Chancellor of the Exchequer. Truss ally Therese Coffey becomes Britain’s first female deputy prime minister and also leads the health ministry as the state-funded National Health Service grapples with soaring demand and depleted resources in the wake of COVID-19. Read:Liz Truss: UK's incoming PM who models herself on Iron Lady Thatcher For the first time, none of the U.K.'s “great offices of state” – prime minister, chancellor, foreign secretary and home secretary – is held by a white man. James Cleverly, whose mother is from Sierra Leone, is foreign secretary and Suella Braverman, who has Indian heritage, has been named home secretary, responsible for immigration and law and order. In her first speech as prime minister on Tuesday, Truss said she would cut taxes to spur economic growth, bolster the NHS and “deal hands on” with the energy crisis, though she offered few details about how she would implement those policies. She is expected to unveil her energy plans on Thursday. British news media reported that Truss plans to cap energy bills. The cost to taxpayers of that step could reach 100 billion pounds ($116 billion). “We shouldn’t be daunted by the challenges we face,” Truss said in her first speech as prime minister. “As strong as the storm may be, I know the British people are stronger.’’