She is the second female to hold the position
Theresa May has officially become Prime Minister of the United Kingdom.
David Cameron travelled to Buckingham Palace earlier this evening to formally hand in his resignation and recommend Theresa May as his successor.
Theresa May then left the Palace and travelled to Downing Street to address the British people for the first time as the new Prime Minister.
Speaking to the world's press outside Number 10, the former Home Secretary said she would lead a "One Nation" government and pledged to create "a country that works for everyone".
In a brief statement she also vowed to tackle injustice, saying "the government I lead will be driven not by the interests of the privileged few".
She will now begin the work of picking her first Cabinet, and it is anticipated that she will choose a record number of women for senior Government positions.