Under-fire British Prime Minister Liz Truss has made a dramatic U-turn by deciding not to freeze a planned corporate tax increase. She has also sacked her finance minister less than 40 days into office.

At a news conference on Friday, she said, "We need to act now to reassure the markets of our fiscal discipline."

Truss also said Chancellor of the Exchequer Kwasi Kwarteng has been replaced by former Foreign Secretary Jeremy Hunt.

Truss seeks to tackle record inflation by promoting economic growth through major tax cuts. Her administration also plans to provide financial support to households and businesses struggling with rising energy costs.

This is not her first U-turn. On October 3, Truss reversed course on a plan to lower the top rate of income tax after being criticized as giving preferential treatment to the wealthy.

Members of both the opposition and ruling Conservative Party are questioning whether Truss is fit for office.

But she vowed not to resign, saying, "I want to deliver a low-tax, high-wage, high-growth economy. It is what I was elected by my party to do, that mission remains."

In a survey this week, 23 percent of respondents supported the Conservatives. That's far behind the 51 percent who backed the Labour party.