The picture has been widely mocked, leading Iain Martin, the paper’s political commentator, to question whether the Prime Minister wouldn’t be better off just leaving social media altogether.

“The latest Cameron picture and tweet show that we have passed well beyond the point where senior politicians engaging with social media is doing them, or us, any good,” he writes.

He certainly has a point. UK Chancellor (finance minister for those not familiar with British politics) George Osborne was ridiculed for trying to pose as a man of the people by tweeting a picture of himself eating a burger which turned out to be from a gourmet restaurant rather than Burger King. And US President Barack Obama is no stranger to some rather substance-free images on social media.

So is social media simply beneath the dignity of politicians? And senior business people for that matter?

I don’t believe so for a second. The problem is not that they shouldn’t be doing it; it’s that they’re not doing it right.

Social media is all about credibility. If you have genuine knowledge of a subject area, if you share useful information and insights, then with a little hard work you can soon build up a respectable following.

Politicians should be using social media to discuss policy decisions, and to be fair to all those named in this article, they do. The problem is that when they try to portray themselves as being down to earth – by eating burgers or chatting on the phone – it’s not credible. We simply don’t think that they are like the rest of us, and don’t believe it when they try to act like they are (and perhaps that’s no bad thing – I wouldn’t want someone like me running the country).

The secret for anyone planning social media for a public figure or business leader is simple: figure out in which area you have credibility, and stick to it.

And never forget that the general tone of social media is not exactly respectful of authority, nor tolerant of people in the public eye pretending to be something they clearly are not.

Try to fool people and, well, they will have the last laugh: