With just 45 days in office, Liz Truss has become the shortest-serving prime minister. The second shortest-serving PM was George Canning who served for 119 days before he died in office in 1827.
Following the announcement, she will stand down as Conservative leader immediately but will remain prime minister for another week whilst her party selects her replacement.
Truss came under intense pressure after a mini-budget was announced on September 23 by her former chancellor, Kwasi Kwarteng introducing billions of pounds worth of unfunded tax cuts.
Since then, Conservative disquiet turned into widespread anger within the parliamentary party. On Wednesday, the Home Secretary; Suella Braverman announced her resignation saying she sent official documents from her private email.
While noting that she had notified the British monarch, who is the head of state, of her resignation as Tory leader, she revealed that there will be an election to choose a new prime minister in the coming week and will remain in office till then.
Her resignation comes after she met the chairperson of the 1922 Committee of backbench as calls for her resignation intensified.