Johnson, a former Mayor of London, has long held leadership ambitions. He has been an arch critic of May’s Brexit approach — although he ultimately voted in favor of her plan on the third occasion it was placed before lawmakers.
He is a favorite among grassroots Conservative members but has faced opposition in the past from a significant number of the party’s MPs.
Widely expected to run for the Conservative leadership in the aftermath of the 2016 Brexit referendum, Johnson dramatically changed course after his former pro-Brexit ally Michael Gove announced his candidacy.
Johnson has supported leaving the EU without a deal, a scenario economists have warned would have a severe financial impact.
He has called Africans “piccaninnies” and Papua New Guineans “cannibals,” and once referred to Hillary Clinton as a “sadistic nurse in a mental hospital.” Johnson also wrote last year that Muslim women wearing burqas resemble “letter boxes.”
An MP since 2001, Johnson will face stiff opposition in what is anticipated to be a crowded field of candidates. The winner will not only take control of the Conservative Party, but also become prime minister and take center stage in the chaotic and fractured Brexit process.
Britain is currently scheduled to leave the European Union on October 31, having twice delayed its departure.