He took office with a resounding pledge to defy the “doubters and the doomsters” by taking the country out of the European Union by the end of October — a task that defeated his predecessor, Theresa May. Johnson’s first act was to oversee a bloodbath of Cabinet ministers, firing supporters of his rival for the top job, Jeremy Hunt, and installing loyalists who had backed his campaign to succeed May.In accordance with British constitutional protocol, he was officially invited to form a government by Queen Elizabeth II at Buckingham Palace on Wednesday afternoon, after winning the race to replace May as leader of the governing Conservative Party earlier this week.In a rousing speech outside the famous black door of 10 Downing Street, Johnson paid tribute to his predecessor but blamed her failure to achieve Brexit on “pessimists” and “critics” who had talked Britain down. “The doubters, the doomsters, the gloomsters, they are going to get it wrong again,” he promised.Read More”The people who bet against Britain are going to lose their shirts,” he said, pledging that Britain would leave the EU on October 31, “no ifs, no buts.”The Queen meets Johnson at Buckingham Palace on Wednesday. In the following few hours, he dispatched all but one of the senior Cabinet members who had not supported his leadership bid. Hunt lost his job as foreign secretary, revealing that he had turned down another role in Cabinet, widely reported to be the less senior position of defense minister. Johnson would have his “full support,” Hunt said.Chaotic momentKnown for his tousled shock of blonde hair and brash style, Johnson enters Downing Street at a chaotic moment for the UK, both at home and abroad. Despite his Conservative Party’s flimsy majority in Parliament, Johnson has pledged to do in three months what May could not do in three years — lead Britain out of the EU, “do or die.” Official forecasts suggest that the latter scenario — breaking out of the bloc without any deal in place — risks triggering a recession and the British pound taking a nosedive.On Wednesday, Johnson said the UK must prepare for the “remote possibility” of a no-deal scenario. “With high hearts and growing confidence,” Britain will prepare for no deal, Johnson said. Using typically Churchillian rhetoric, he said the banks, the farms and the rest of the country “will be ready.”Beyond the political bedlam in Britain, Johnson inherits a mounting crisis with Iran. Tehran’s seizure of a British-flagged oil tanker last week has thrust the UK into the middle of a standoff between Tehran and Washington.He once wanted to be king of the world. Now Boris Johnson has his crownAll of this falls in the lap of one of the most divisive politicians of his generation, who has said much on Brexit, Iran and many other topics, but has so far divulged little about any potential plan for his premiership.”He’s made a big pitch of re-energizing the country and bringing back optimism as a way he wants to do things,” Tim Durrant, a senior researcher at the London-based Institute for Government think tank, told CNN. “We’ll see if he has any details on the actual issues.”Johnson, a former mayor of London and British foreign secretary, won the race to lead his party with 66% of the votes. The election was triggered after an embattled May was forced to quit after losing the support of her Cabinet, many of whom were exasperated with her inability to secure Brexit.As Prime Minister, Johnson, 55, takes on the same problems that faced May — a deeply divided Parliament and and a fractured nation — but under even more pressured circumstances.”Even though Boris faces the same issues that May was confronted with when she took office … the context of those issues is much different in terms of the parliamentary arithmetic and timing,” Durrant said. Photos: In photos: British Prime Minister Boris JohnsonBritain’s new Prime Minister, Boris Johnson, waves from the steps of No. 10 Downing Street after giving a statement in London on Wednesday, July 24.Hide Caption 1 of 20 Photos: In photos: British Prime Minister Boris JohnsonA 21-year-old Johnson speaks with Greek Minister for Culture Melina Mercouri in June 1986. Johnson at the time was president of the Oxford Union, a prestigious student society.Hide Caption 2 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson started his career as a journalist. He was fired from an early job at The Times for fabricating a quote. He later became a Brussels correspondent and then an assistant editor for The Daily Telegraph. From 1994 to 2005, he was editor of the weekly magazine The Spectator.Hide Caption 3 of 20 Photos: In photos: British Prime Minister Boris JohnsonIn 2001, Johnson was elected as a member of Parliament. He won the seat in Henley for the Conservative Party.Hide Caption 4 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson looks apologetic after fouling Germany’s Maurizio Gaudino during a charity soccer match in Reading, England, in May 2006.Hide Caption 5 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson is congratulated by Conservative Party leader David Cameron, right, after being elected mayor of London in May 2008. Cameron later became prime minister.Hide Caption 6 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson, left, poses with a wax figure of himself at Madame Tussauds in London in May 2009.Hide Caption 7 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson poses for a photo in London in April 2011. He was re-elected as the city’s mayor in 2012.Hide Caption 8 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson and his wife, Marina, enjoy the atmosphere in London ahead of the Olympic opening ceremony in July 2012. The couple separated in 2018 after 25 years of marriage. Hide Caption 9 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson gets stuck on a zip line during an event in London’s Victoria Park in August 2012.Hide Caption 10 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson poses with his father, Stanley, and his siblings, Rachel and Jo, at the launch of his new book in October 2014. Stanley Johnson was once a member of the European Parliament.Hide Caption 11 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson takes part in a charity tug-of-war with British military personnel in October 2015.Hide Caption 12 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson kisses a wild salmon while visiting a fish market in London in June 2016. A month earlier, he stepped down as mayor but remained a member of Parliament for Uxbridge and South Ruislip.Hide Caption 13 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson arrives at a news conference in London in June 2016. During the Brexit referendum that year, he was under immense pressure from Prime Minister Cameron to back the Remain campaign. But he broke ranks and backed Brexit at the last minute.Hide Caption 14 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson sits next to Prime Minister Theresa May during a Cabinet meeting in November 2016. Johnson was May’s foreign secretary for two years before resigning over her handling of Brexit.Hide Caption 15 of 20 Photos: In photos: British Prime Minister Boris JohnsonAs foreign secretary. Johnson meets with US House Speaker Paul Ryan in April 2017. Johnson was born in New York City to British parents and once held dual citizenship. But he renounced his US citizenship in 2016.Hide Caption 16 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson launches his Conservative Party leadership campaign in June 2019.Hide Caption 17 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson and Foreign Secretary Jeremy Hunt take part in the Conservative Leadership debate in June 2019.Hide Caption 18 of 20 Photos: In photos: British Prime Minister Boris JohnsonJohnson speaks in July 2019 after he won the party leadership vote to become Britain’s next prime minister.Hide Caption 19 of 20 Photos: In photos: British Prime Minister Boris JohnsonBritain’s Queen Elizabeth II welcomes Johnson at Buckingham Palace, where she invited him to become Prime Minister and form a new government.Hide Caption 20 of 20Throughout his leadership campaign, Johnson was vocal about his readiness to take Britain out of the EU without a deal, pledging to leave on October 31, the latest deadline for the UK to depart the bloc.If he cannot negotiate a new deal with the EU, Johnson has said that he’d be willing to force Brexit through on that date. He has refused to rule out suspending parliament in order to do so. Johnson promised Wednesday to do a better deal with Brussels in less than 99 days, “because the British people have had enough of waiting.” “I will take personal responsibility for the change I want to see… never mind the backstop, the buck stops here,” Johnson said, referring to an insurance policy designed to avoid a hard border between Northern Ireland and the Republic of Ireland.But, given that the EU says it isn’t interested in reopening the Withdrawal Agreement — the deal that May signed with the bloc in 2018 but has been repeatedly rejected in Parliament, Johnson has his work cut out.