New Prime Minister Theresa May has made Boris Johnson, the former London mayor who led the Brexit campaign, foreign secretary in her new government.
He replaces Philip Hammond, who becomes chancellor. Ex-Energy Secretary Amber Rudd has been appointed home secretary.
No 10 said ex-Chancellor George Osborne had resigned from the goverment.
On arriving at Downing Street, Mrs May vowed to lead a "one nation" government that works for all not just the "privileged few".
The UK's second female prime minister promised to give people who were "just managing" and "working around the clock" more control over their lives.
Michael Fallon continues as defence secretary, and Liam Fox, who resigned as defence secretary in 2011, has a new role as international trade minister.
On Twitter, Mr Osborne, who was chancellor throughout Mr Cameron's tenure, said it had been a "privilege", adding: "Others will judge - I hope I've left the economy in a better state than I found it."