Dominic Raab, the man at the helm of the British government while Boris Johnson is hospitalised, has been both an ally and a rival to his boss.
During the Brexit campaign in 2016, Raab campaigned alongside Johnson successfully to break away from the European Union. Three years later, the pair stood against each other in the Conservative Party's leadership contest.
Johnson won, and then triumphed again in the general election that followed - but it is Raab, a former Foreign Office lawyer, who is now in charge of the government as the prime minister receives treatment in intensive care.
"There's an incredibly strong team spirit behind the prime minister," Raab said late on Tuesday. He said he and his colleagues are focused on ensuring Johnson's instructions are "implemented as soon as possible."
Raab, 46, has been in Parliament since 2010, but he struggled to rise under former Prime Minister David Cameron. Instead, he became a troublemaker, asking awkward questions of the government and then backing Brexit. That upset voters in his southwest London district, and he came close to losing the usually safe Conservative seat in last year's election despite a national surge for the Tories.
His chance for prominence came in 2018 when then-Brexit Secretary David Davis resigned. The prime minister at the time, Theresa May, needed someone with solid pro-Brexit credentials capable of handing negotiations with the EU. She settled on Raab. But he lasted less than five months in the job before following Davis out of the door in protest at May's strategy.
He ran for the party leadership in 2019, making it to the final six before being eliminated. His endorsement of Johnson at that point probably helped him to his current role of foreign secretary.
The success of Raab's interim leadership will largely depend on the co-operation of key cabinet minister Michael Gove, who also stood to become Tory leader last year before his campaign bid was derailed by allegations about his use of cocaine. Gove is co-ordinating the government's response to the pandemic.
"So far, we have proceeded completely by consensus and we do so in a team way," Gove told BBC News on Wednesday.
The kind of clever lawyer who doesn't mind telling people they are wrong, Raab can irritate others. But he has also been a conciliator, and is probably the only member of Parliament to have both lived on an Israeli kibbutz and studied at Birzeit University, near Ramallah. He has worked for Dominic Grieve, a leading Tory pro-European, and arch-Brexiter Davis.
The son of a Jewish Czech refugee who was raised in the Church of England before marrying a Brazilian Catholic, Raab defies easy categorisation: sometimes blunt, sometimes charming. He studied law at Oxford University before obtaining a masters degree at Cambridge. He worked for law firm Linklaters LLP before joining the Foreign Office, leading a team in The Hague to bring war criminals to justice.
In 2011, Raab dubbed feminists as "obnoxious bigots" in an online article in which he also claimed men were getting "a raw deal." May accused him of fueling "gender warfare." When he stood to become Tory leader in 2019, Raab raised eyebrows when, asked about his approach to feminism, he defended his record by saying he "picks up the slack" at home.
Three years ago, Raab was branded "offensive" by then-Liberal Democrat leader Tim Farron after saying "the typical user of a food bank isn't someone that's languishing in poverty; it's someone who has a cash flow problem."
In 2012, he co-authored a 2012 book in which he blasted British workers for being "among the worst idlers in the world."
That sense of determination is a key trait. A karate black belt, Raab trained and fought so hard he had to have a hip replaced in his mid-thirties.