LONDON — David Cameron won't be around for ever, and that's according to the man himself.

The prime minister has ruled out the possibility of a third term in office, saying that he'll stand for a second term but after that "it will be time for new leadership." It would mean a new prime minister or leader of the Conservative party by 2020.

In an informal interview with the BBC's deputy political editor James Landale in his Cotswolds home, he compared his political career to breakfast.

“I’ve said I’ll stand for a full second term, but I think after that it will be time for new leadership. Terms are like shredded wheat: two are wonderful but three might just be too many,” he said.

Two Shredded Wheat, which is just the right serving according to David Cameron.

Asked if that meant he wouldn't stand for a third time he said: “No. I think I’m standing for a full second time."

"I’m not saying all prime ministers necessarily definitely go mad or even go mad at the same rate. But I feel I’ve got more to bring to this job, the job is half done, the economy’s turned round, the deficit is half down. I want to finish the job.”

Cameron then went as far as to suggest three names as possible replacements: Home Secretary Theresa May, Chancellor of the Exchequer George Osborne, and Mayor of London Boris Johnson.

“There definitely comes a time where a fresh pair of eyes and fresh leadership would be good. The Conservative party has got some great people coming up – the Theresa Mays and the George Osbornes and the Boris Johnsons. There is plenty of talent there. I am surrounded by very good people.”

His comments were met with dismay from some quarters. Douglas Alexander, Labour's chair of general election strategy said it was "typically arrogant of David Cameron to presume a third Tory term in 2020 before the British public have been given the chance to have their say in this election” while a Liberal Democrats spokesperson called his comments "presumptuous."

Conservatives have rushed to his defence. Chief Whip Michael Gove said on Newsnight it was a "statement of the bleeding obvious" while Defence Secretary Michael Fallon called it a "straight" and "obvious" answer on the Radio 4 Today show. Boris, who was questioned on a morning run, said: "All he's saying is I think obvious and common sense, which is that he doesn't want to go on and on and on like Mrs Thatcher."

In the UK, there is no time limit on the prime minister's term of office. The longest serving prime minister of recent times was Margaret Thatcher, who held the position from 1979 to 1990.

Cameron is due to participate, along with Ed Miliband, in a Q&A programme on Channel 4 and Sky News presented by Jeremy Paxman and Kay Burley on Thursday Mar 26.