Cameron, while rehearsing a speech in Leeds on stepping up the level of local devolution in the area, was caught on a BBC microphone joking among a small group of colleagues.
At one point he said: "We just thought people in Yorkshire hated everyone else – we didn't realise they hated each other so much."
The full conversation reads:
Cameron: I'll say... Delighted there's been such a strong response. Time to look at all the proposals that have been made. Obviously the more politicians can come together locally to come up with preferred solutions the better. But one way or another...
Unidentified man: The fact is there will be some devolution coming to Yorkshire, but what form that takes...
Cameron: We just thought people in Yorkshire hated everyone else – we didn't realise they hated each other so much.
It's fair to say people from Yorkshire haven't really taken the jibe very well.
Not very well at all, actually.
But mostly, people can't believe he's fallen for the old off-camera microphone trick that caused trouble for Gordon Brown back in the 2010 general election campaign.
UPDATE: Cameron told BBC Radio Five Live that he was expecting "a bit of gyp" for his comments.
I was picked up saying something which was not meant to be broadcast, but it was a joke. One of my aides had said to me there were about five or six different bids from Yorkshire for devolution – different ideas from different parts of Yorkshire – and I joked saying I thought Yorkshiremen had it in for everyone else but not for each other, or words to that effect, which was a total joke but it's been picked up and I suspect I'll be getting a bit of gyp for this.
Jamie Ross is a Scotland reporter for BuzzFeed News and is based in Edinburgh.
Contact Jamie Ross at firstname.lastname@example.org.
Got a confidential tip? Submit it here.