Foreign secretary Liz Truss seems to have gained the advantage so far.
Sunak's resignation helped trigger a revolt that saw Prime Minister Boris Johnson agree to step down after a series of scandals. Members of the ruling Conservative Party will vote for a successor over the summer, with an announcement due on Sept. 5.
But it is foreign secretary Liz Truss who seems to have gained the advantage so far among the 200,000 members of the governing party who will ultimately choose the winner. "Be in no doubt, I am the underdog," Sunak said in a speech in Grantham, central England, the birthplace of former prime minister Margaret Thatcher.
"The forces that be want this to be a coronation for the other candidate but I think members want a choice and they are prepared to listen," he said.