Theresa May formally steps down as leader of UK

File photo taken on June 27, 2016 shows then British Home Secretary Theresa May arriving for a cabinet meeting at 10 Downing Street in London, Britain. Newly-elected Conservative Party leader Boris Johnson took office as the British prime minister on Wednesday amid the rising uncertainties of Brexit. The latest development came after Theresa May formally stepped down as the leader of the country and Johnson was invited by the Queen to form the government. (Xinhua/Han Yan)