Nouveau Rishi

The former chancellor looked finished when he lost to Liz Truss, but now Rishi Sunak is Britain's third prime minister in two months. Can a man twice as rich as the king lead the country through a cost of living crisis?

- Peter Walker and Pippa Crerar

Rishi Sunak was confirmed as Britain's third prime minister in less than two months on Monday, after another week of political turmoil which saw the embattled Liz Truss resign last Friday. He saw off the leadership challenges of rivals Penny Mordaunt and former prime minister Boris Johnson, who had attempted an audacious but shortlived comeback bid.

In his first address to MPs on becoming party leader, Sunak told them that the ruling Conservative party was facing an "existential threat" and that it should "unite or die". He vowed he would return the party to the values of its 2019 manifesto, which helped win the party an 80-seat majority. Ruling out an early general election, he said he would lead a government of serious Conservative values and make his first priority tackling the economic crisis..

Sunak, who became prime minister without MPs or members having voted for him after his rivals withdrew to leave him as the only candidate, formally took over from Truss after meeting the King at Buckingham Palace on Tuesday.

One of the many unlikely knock-on effects of Truss's ultra-brief time as prime minister is the fact that when her successor walked into No 10 this week, the political obituaries that wrote him off as the nearly man of modern UK politics were just seven weeks old.

Had Johnson successfully returned it would have been viewed as an extraordinary and unprecedented comeback.

But in some ways Sunak's career resurrection has been just as unlikely.

Sunak's loss to Truss in a vote of Tory members announced on 5 September was not crushing, at 57% to 43%. But the moment the contest moved from Conservative MPs to the party rank and file, he never once looked like winning.