In a carefully orchestrated political ballet, Cameron made his final appearance as prime minister in Parliament, turning the usually raucous prime minister's questions session into a time for praise, thanks, gentle ribbing, cheers - and a sprinkle of criticism.
The monarch will then call on May, now the interior minister, to form a government and the newly-anointed prime minister will make a statement outside her new Downing Street residence.
The 59-year-old, who will become Britain's second female prime minister after Margaret Thatcher, also has to attempt to bridge Conservative Party divisions and deal with a potential economic downturn.
Graham Brady, head of the 330-strong Conservative faction in parliament, said there were still constitutional procedures to be observed before her appointment could be confirmed, but he aimed to make a confirmation announcement as soon as possible. "That would be good for the United Kingdom and good for Scotland".
"The task of the new prime minister. will be to get clarity on the question of what kind of relationship Britain wants to build with the European Union", Chancellor Angela Merkel told a news conference.
The daughter of a Church of England pastor, May is a cricket fan with a sober, well-mannered demeanour who lists her hobbies as cooking and walking.
Justice Secretary Michael Gove arrives in Downing Stree for the final Cabinet meeting with David Cameron as Prime Minister.
THERESA MAY has underlined her determination to resist calls for a general election as she prepares to become prime minister tomorrow.
"He has been kicked so many times but he says 'Keep going, it is only a flesh wound, I admire that, " Cameron said. After all, as I once said: ""I was the future once"," said Cameron, who has said he intends to carry on as a backbench Conservative party MP for Witney in Oxfordshire.
British police stand guard Tuesday in London as movers load Prime Minister David Cameron's belongings from the official quart.
She has quite the task.
Despite pressure from other European Union capitals to quickly start negotiating the terms of Britain's exit, May has said she would not be rushed into triggering article 50 of the EU's Lisbon Treaty, the formal step that will kickstart the process.
Mr. Cameron stepped down after Britons rejected his entreaties and voted in a June 23 referendum to quit the European Union, weakening the 28-nation bloc and creating huge economic uncertainty.
Cameron will later pack up his final possessions and move out of the Number 10 Downing Street office leaving behind one key ally: Larry the cat. Since the vote, she has repeatedly said that "Brexit means Brexit" and her backers say she is determined to make the exit a success. "I have. concluded that the interests of our country are best served by the immediate appointment of a strong and well supported prime minister".
Replying to Labour leader Jeremy Corbyn, who is facing his own leadership challenge, Cameron poked fun at Labour's leadership turmoil, noting that the Tories had had "resignation, nomination, competition and coronation" while Labour is still working out the rules for its contest.
"As someone who has also received death threats this week and previously, I am calling on all Labor Party members and supporters to act with calm and treat each other with respect and dignity, even where there is disagreement", Corbyn said.