Rishi Sunak will become the UK’s first British Asian prime minister after his only remaining rival pulled out of the Tory leadership contest.
Nearly 200 Conservative MPs publicly backed the former chancellor ahead of the nomination deadline on Monday.
Commons Leader Penny Mordaunt dropped out after failing to secure enough support among MPs.
It means Sunak will succeed Liz Truss and become the youngest PM for more than 200 years.
Sunak – a 42-year-old practising Hindu – is expected to take office in the coming days now the result of the Tory leadership contest is known.
Sunak has addressed Tory MPs after the result was announced by Sir Graham Brady, the chairman of the 1922 committee of backbench Conservatives.
In the speech – which took place behind closed doors – Sunak told them this was going to be a tough period and ruled out an early general election, MP Simon Hoare said.
Sunak’s coronation, in effect, as Tory leader caps a rapid political comeback by the former chancellor after he lost out to Truss in the last leadership contest during the summer.
Truss – whose tax-cutting agenda Sunak dismissed as “fairytale economics” – tweeted to congratulate him and offer her “full support”.
Her successor will take office at a time of economic crisis and pressure on public finances, exacerbated by Truss’s mini-budget, which has been mostly scrapped.
Conservative Party Chairman Jake Berry said it was time for the party to “unite four-square behind Rishi” after a period of intense political turmoil under Truss’s premiership.
Mordaunt withdrew from the latest contest minutes before the result was announced, admitting it was “clear that colleagues feel we need certainty today”.
“This decision is an historic one and shows, once again, the diversity and talent of our party,” Mordaunt wrote in a tweet. “Rishi has my full support.”
Mordaunt took the leadership race to the wire but came under pressure to unite behind Sunak after former Prime Minister Boris Johnson withdrew from the contest on Sunday.
Johnson – who resigned as prime minister only seven weeks ago – claimed he had enough support to stand but acknowledged now was “not the right time”.
Sources told the BBC that Sunak and Johnson met on Saturday as Tory MPs decided who to back in the second Tory leadership contest in four months.