Why Cameron's Casual Chit-Chat Is A Gamble

It came out as a bit of kitchen chit-chat in front of the cameras.

David Cameron, in the casual blue shirt he usually saves for holiday photo shoots in Cornwall, seemed relaxed and frank as he speculated on his career five years down the line.

The question: Would he, given the chance, stay on to serve a third term?

A slightly premature inquiry some might say - having not won yet a second - but the Prime Minister had a clear answer - he would decline.

If it was an off-the-cuff comment Mr Cameron was quick to cook up a Forest Gump-style metaphor to explain his reasoning.

"Terms are like Shredded Wheat," he told the BBC's James Landale.

"Two are wonderful - three might be too many."

The comment took many by surprise - the casual nature of the interview led some to speculate he'd been caught off-guard.

Political commentator Dan Hodges joked: "He made the classic political mistake of giving a straight answer to a straight question - which of course you should never do."

But Labour's Douglas Alexander wasn't amused and described the comment as "typically arrogant".

Labour's Chair of General Election Strategy said: "Instead of focusing on themselves, it is time we had a Government focused on the needs of working families."

If Mr Cameron was having a moment of self-indulgence, it wasn't exactly self-promotion - he was even happy to speculate about successors, suggesting Theresa May, George Osborne and Boris Johnson as likely candidates.

It seems the Prime Minster has calculated that it will reassure voters to know that he doesn't plan to outstay his welcome in the way Tony Blair and Margaret Thatcher clung to power - the latter once saying she hoped "to go on and on".

But it's a gamble, because it raises questions about the Prime Minister's timetable and his potential successors' ambitions - questions that will now rumble on for as long as Mr Cameron remains in office.

Sean Worth, a former advisor to Mr Cameron, said: "It's a good message for politicians to say I'm in this for a limited amount of time, but whether it's a good thing before a second term, I'm not so sure.

"It does open up that question, which is how long have we got you for if we do elect you?"

First to dampen speculation was Mr Johnson. The London Mayor said: "Frankly people are making a fuss about nothing.

"What the Prime Minister is saying is that he is going to serve until 2020, which is, by the way, exactly what we need."

The smile suggested he didn't mind that, following Mr Cameron's comment, journalists came straight to his door.