Elected for the first time to parliament in 2015, Rishi Sunak became Britain's youngest prime minister in more than 200 years this afternoon, tasked with steering the country through an economic crisis and mounting anger among some voters.
ECONOMIC POLICIES
In a statement issued on Sunday announcing his candidacy, Sunak said the country faced a "profound economic crisis".
As finance minister between February 2020 and July 2022, he set Britain on course to have its biggest tax burden since the 1950s. He also set out higher public spending but simultaneously promised more discipline and to cut waste.
During the summer leadership campaign he criticised Truss's tax-cutting agenda, saying he would instead only cut taxes once inflation had been brought under control. At the time he outlined a plan to cut income tax from 20% to 16% by 2029.
Sunak has backed the independence of the Bank of England and stressed the importance of government policy working alongside the central bank to tame inflation, not exacerbating it.
POLITICAL CHALLENGES
One of Sunak's first challenges will be to show he can control a Conservative Party that has a large majority in parliament but is riven with factions that differ on key issues like Brexit and immigration as well as economic management.
Higher taxes will be strongly opposed by some in the party; others will oppose spending cuts in key areas like health and defence.
Winning the leadership contest would be only the first step in uniting a party that has ousted its last two leaders over internal differences, and spent years arguing with itself over how to leave the European Union.
Sunak supported Brexit in the 2016 referendum but is still seen by some on the right of the party as too sympathetic to the EU.
The key issue of trade with Northern Ireland is still being negotiated with Brussels. Sunak would face pressure to get a deal that rewrites parts of the initial exit agreement without conceding to a lasting EU say over trade between Britain and Northern Ireland.
He will also face calls to follow through on government promises to control immigration into the country, an issue which many Conservative lawmakers see as critical to winning over voters at the next election.
POLITICAL POLICIES
Sunak's campaign launch statement on Sunday said he wanted to "fix our economy, unite our party and deliver for our country."
On Northern Ireland, Sunak previously said he would push on with legislation designed to unilaterally overrule the Brexit deal while still trying to negotiate with the EU. The bill, currently in parliament, has been heavily criticised by the EU.
On Brexit more broadly, in August he promised to "keep Brexit safe" and set up a new governmental unit to review EU regulations that still apply in British law.
In the summer leadership contest, he said he was proud to come from a family of immigrants but he believed Britain must control its borders, and would retain a plan to deport asylum seekers to Rwanda.
He also refused to rule out Britain's withdrawal from the European Court of Human Rights.