Lib Dem leader Nick Clegg will be his deputy after they agreed to the UK's first coalition government in 70 years.

Mr Cameron, who at 43 is the youngest PM in nearly 200 years, vowed to set aside party differences and govern "in the national interest".

Mr Clegg said he acknowledged some Lib Dem voters would have doubts about the deal but urged them to "keep faith".

Mr Cameron's party won the most seats in the general election last week, but not enough to secure an overall Commons majority, resulting in a hung Parliament.