Accompanied by his pregnant wife Samantha, David Cameron arrived at number 10 Downing Street on Tuesday evening after accepting the Queen's request to form a government.
His appointment as prime minister follows the resignation of Gordon Brown, who has also stepped down as Labour leader.
Mr Cameron's Conservative Party won the most seats in the UK election last week, but failed to gain an overall majority.
He said he aimed to form a "proper and full coalition" with the Liberal Democrat party to provide a "strong, stable government".
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