On her fiftieth day in office , she stepped down amid a government crisis , making her the shortest-serving prime minister in British history. Truss studied philosophy, politics and economics at Merton College, Oxford , and was the president of the Oxford University Liberal Democrats. In she joined the Conservative Party. After two unsuccessful attempts to be elected to the House of Commons , she became the MP for South West Norfolk at the general election.
As a backbencher she called for reform in several policy areas including the economy, childcare and mathematics in education. Truss was the parliamentary under-secretary of state for childcare and education from to before Cameron appointed her secretary of state for the environment, food and rural affairs in a cabinet reshuffle. Although she campaigned for Britain to remain in the European Union , Truss supported Brexit following the outcome of the referendum. Following Cameron's resignation in his successor, Theresa May, appointed her secretary of state for justice and lord chancellor , making Truss the first woman to serve as lord chancellor in the office's thousand-year history; in the aftermath of the general election she was demoted to chief secretary to the Treasury.
After May announced her resignation in May Truss supported Johnson's successful bid to become Conservative leader and prime minister. He appointed Truss secretary of state for international trade and president of the Board of Trade in July and subsequently to the additional role of minister for women and equalities in September.
Johnson promoted Truss to foreign secretary in the cabinet reshuffle ; during her time in the position she led negotiations on the Northern Ireland Protocol and the British response to the Russian invasion of Ukraine.
In September Truss defeated Rishi Sunak in a leadership election to succeed Johnson, who had resigned because of an earlier government crisis , and was appointed as prime minister by Elizabeth II two days before the monarch's death ; her government's business was subsequently suspended during a national mourning period of ten days. In response to the rising cost of living and increased energy prices , her ministry announced the Energy Price Guarantee.
