Davos is not the easiest place in the world to get to – four trains and a plane from London unless you drop in by Lear jet. So it seems puzzling, if you are prime minister-in-waiting, to come all this way and then say nothing that can be reported.

About three dozen journalists made a fairly long trek through the snow at lunchtime to hear David Cameron being interviewed by Christine Ockrent, the former French TV anchor. I counted at least a dozen editors, together with distinguished columnists and publishers from Europe, America, India and the Middle East. But about five minutes in, Cameron announced it was all off-the-record.

I checked with Andy Coulson, his chief spokesman. Yes, "Davos terms," he confirmed. I checked with the Davos big cheeses. Cameron had insisted, they said. The net result is that I can't tell you what he said.

I can tell you who was there, and I guess I can tell you what they asked. In addition to Ockrent, there were four British editors (Guardian, Telegraph, Times, FT). Shekhar Gupta, editor of the Indian Express, was there, with other colleagues from India. There was the publisher of the New York Times, Arthur Sulzberger Jr, Jacob Weisberg of Slate and Josef Joffe, publisher-editor of Die Zeit. There were columnists from the NYT, Washington Post and several European countries.

What did we talk about? The coming election, class in Britain, multiculturalism, Afghanistan, Obama's plans to clip the wings of the banks, extremist Islam, Europe, the internet, taxation, education, assisted dying and much else.

So why keep it all hidden from our readers? After tweeting my frustration, I got several answers, all on the same track.

"You know why," said Mark Choueke, Marketing Week editor. "They're not in Davos to speak to us, the masses, but to you, the influencers. They want you to become advocates."

"Cameron is focus group testing his lines of argument among the elitest focus group he will ever encounter," tweeted Stephen Murray from Sydney. "'Coz they don't want you to show how clearly full of shit they really are?" suggested bleeters.

Well, yes, there's probably something in all of the above. And then there was Charlie Whelan: "So much for the Guardian's crusade for openness. You don't have to go along with this Tory con man[']s rules."

Well, actually, you probably do if those are the rules stitched up between Teams Cameron and Davos. When Charlie Whelan was spinning for Gordon Brown, he did a very great deal of off-the-record briefing, so if he's now a crusader for openness, he's undergone one of the greatest conversions since Lord Goldsmith changed his mind on resolution 1441.

Cameron presumably had a purpose – and it was probably along the lines of the suggestions above. He wanted a quiet conversation with media people who might become advocates. In any case, he said nothing startlingly new or dramatically interesting – at least for those who have followed him over the years.

But it is faintly ridiculous for a man who might be prime minister within months to be addressing an international meeting of journalists on the condition that none of it was reported.

• This article was amended on 29 January 2010. The original spelled the Die Zeit publisher-editor's surname as Jofee. This has been corrected.