'He still has his mojo' Cameron failed to find a purpose after No 10. Can he succeed this time?

Four days ago David Cameron was having lunch with friends, including his old cabinet colleague Andrew Mitchell. If F the former prime minister knew then that he would be appointed Mitchell's boss in less than a week - the coup de grace in yesterday's dramatic government reshuffle - he did not let on.

- Kiran Stacey 

"He didn't mention anything about a return to government," said one person who knows what was discussed at the lunch. "But it was clear his appetite for politics was still there." 

Downing Street yesterday revealed that Cameron would be taking over at the Foreign Office, in the most unexpected political return since Gordon Brown appointed Peter Mandelson as business secretary in 2008.

A spokesperson said the prime minister, Rishi Sunak, had approached his predecessor with the idea, though would not confirm reports that the offer was made as late as this weekend.

Cameron becomes the third former prime minister to become foreign secretary since 1900, following Arthur Balfour and Alec Douglas-Home, and the third cabinet minister in recent decades to serve from the House of Lords.

His allies say he was desperate to return to government, having failed to find a role that fulfilled him outside politics. Since leaving Downing Street, Cameron has worked as president of Alzheimer's Research UK and as a teacher at New York University Abu Dhabi, but also more controversially as an adviser to Greensill Capital, the failed financial services company.

Friends say that unlike his great friend George Osborne, who has worked recently as editor of the Evening Standard and chair of the British Museum, Cameron never really enjoyed the private sector.

Osborne himself said on his new podcast, Political Currency: "There was a bit of him... that died inside, which was the public service element which he tried to fill with other things like his very important work for Alzheimer's, but it wasn't the same.

"And now I think, when I was speaking to him about it, it's like the sound of the trumpet, back on the playing field, the political playing fields, and serving your country."