Boris Johnson officially became Britain's Prime Minister after meeting Queen Elizabeth II and will form a “cabinet for modern Britain” with the primary task of finally delivering Brexit.

In his first speech as Britain’s Prime Minister on the steps of Downing Street, Johnson offered an optimistic vision of Britain and his administration that will “crack” the Brexit conundrum and unleash the full potential of the country.

“The British people have had enough of waiting and the time has come to act to give strong leadership. My job is to serve you the people,” he said.

He promised to tackle social problems and improve education, saying he will “take personal responsibility”, adding “the buck stops here.”

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“I am standing before you today, to tell you the British people, that those critics are wrong - the doubters, the doomsters, the gloomsters are going to get it wrong again.” — Boris Johnson

In a message to the European Union, he said that although he wants to have a deal, he will prepare for a potential no-deal fallout “not because we want that outcome, but because it is only common sense to prepare.”

“Yes, there will be difficulties … but if there is one thing that has really sapped the confidence of business is not the decisions we have taken, it is our refusal to take decisions.”

He ended his speech saying “I am standing before you today, to tell you the British people, that those critics are wrong - the doubters, the doomsters, the gloomsters are going to get it wrong again.”

Earlier, Theresa May appeared at the Parliament for Prime Minister Questions (PMQs) earlier today for the last time as the country’s premier, a session that lasted 63 minutes and appears to be the longest PMQs in the country’s history.

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While the atmosphere remained cordial, she clashed with opposition leader Jeremy Corbyn for the last time, who suggested that she should join the opposition to stop “the “reckless” Johnson’s government that promised to lead the country out of the EU with or without a deal.

She ended the exchange by calling on Corbyn to resign, saying “perhaps I could just finish my exchange with him by saying this: as a party leader who has accepted when her time was up, perhaps the time is now for him to do the same?”

“Perhaps I could just finish my exchange with him by saying this: as a party leader who has accepted when her time was up, perhaps the time is now for him to do the same?” — Theresa May

During her farewell speech on the steps of the Downing Street residence, she reiterated that she will continue to serve as a Member of Parliament and believes Britain must leave the EU.

The speech was interrupted by a local anti-Brexit activist who was heard shouting “Stop Brexit” – prompting May to respond, “I think not.”

May then visited the Queen and formally submitted her resignation, allowing the Queen to welcome Johnson and ask him to form the government.

As Johnson was traveling to the Buckingham Palace to see the Queen, his convoy was halted by climate change protesters. Police had to step up to break up a human chain formed by activists that briefly stopped the convoy.

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Johnson promised a “cabinet for modern Britain” as he prepares to take the reins of the country after winning the Conservative Party leadership election on Tuesday against Jeremy Hunt.

Current Home Secretary Sajid Javid, who also ran for the party’s leadership, was first to be announced on Thursday evening as the new Chancellor of the Exchequer, effectively the treasury secretary. Priti Patel replaced Javid as Home Secretary.

Another arch-Brexiteer, Dominic Raab replaced Hunt, the foreign secretary, who declined another position. He headlined several current cabinet members who either resigned or were sacked. Raab will have his hands full with Brexit, as well as the ongoing Iran crisis and repairing a rift with the U.S. following unflattering comments made about President Trump by U.S. ambassador Sir Kim Darroch, who subsequently resigned.

Johnson, an avid supporter of Brexit, will attempt to succeed where May failed – getting Britain to honor the 2016 referendum result and leave the EU by the Oct. 31 deadline.

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Chief EU Brexit negotiator Michel Barnier said “we are ready to listen and to work with” Johnson, but didn’t budge on the union’s refusal to revisit the deal.

“A no-deal Brexit will never be, never, the choice of the EU. But we are prepared,” he said in Brussels.

But the new incoming prime minister said Tuesday that he will deliver Brexit “in a new spirit of can do,” adding “I say to all the doubters: ‘Dude, we are going to energize the country, we are going to get Brexit done.’”

The Associated Press contributed to this report.