We all do it -- journalists, historians, even human beings. We all tinker with the truth in order to create an actuality that feels more truthful than the truth itself. How many times have you deliberately misquoted someone in order to make that anecdote a little bit funnier? How many times have you retrospectively put words into your own mouth in order to banish an espirit d'escalier? How quickly "I wish I'd said" becomes "what I said"! In fact, claiming that you said something you meant to say is considered so acceptable that even MPs are allowed to edit their speeches in Hansard. The relationship between what actually happened and what we say that happened is a fraught one, as every police detective will tell you.

I'm having a similar problem with my current book project, which is a new history of the Great Escape. Some of the RAF officers' memoirs are at such a huge variance to what they told MI9 investigators after the war, that it is now almost impossible to even get near the truth. This isn't because they were liars (OK, a couple were), but because they had told the stories so many times, over so many decades, that the natural tendency to exaggerate, inflate, massage and entertain has twisted the truth into something that is nearer to fiction than fact. For historians, the best you can do is to go with what your knowledge tells you is right, and to trust testimony made nearer the event than, say, at a speech made at a golf club last week. Anyway, for me, chasing the unobtainable -- that is, the truth -- is part of the fun of writing history.

Because the truth is a flakey place indeed, I'm somewhat sympathetic to the plight in which Johann Hari of the Independent now finds himself. Journalists face the same problem of representing the truth as historians, but they have to deal with it on a much tighter timescale. And, unlike historians (ahem), journalists are under a lot of pressure to deliver something punchy and immediately appealing. In other words, the temptation to sex up the dossier is huge.

I remember once writing a piece for the Times on the archaeological work going on at London Bridge during the building of the new Tube station. My features editor asked whether we could say that the archaeologists had discovered a Roman brothel. I said it was possible, as there were often brothels at the entrances to cities, but there was no proof. He told me to put that in, and -- you've guessed it -- he cut out my disclaimer, and the piece appeared the next morning claiming that the Museum of London had found a Roman brothel. Cue angry letter, which I left him to deal with.

But former colleagues and I did worse, far worse. One was sent to Heathrow Airport to interview women in WH Smith about their holiday reading. Unsurprisingly, he couldn't be bothered to go, and he went back home and wrote the piece from there. I recall chucking in the odd line to this great work of fiction. I was particularly proud of my "totally made up woman in her late 30s", the ambiguity of which sailed very close to the wind. In the mid 1990s, I once covered a Rolling Stones comeback concert in Sheffield for the news pages in which I was supposed to interview members of the audience, but I was too gauche for some reason, and just made up the quotes, because -- and this is perhaps salient -- I thought my quotes would better tell the story than the people I was supposed to be talking to.

Because of my guilty hack past, I initially found it hard to throw stones at Hari's misleading insertion of interviewees' previously spoken or written words into an interview. His justification seems almost plausible:

So occasionally, at the point in the interview where the subject has expressed an idea, I've quoted the idea as they expressed it in writing, rather than how they expressed it in speech. It's a way of making sure the reader understands the point that (say) Gideon Levy wants to make as clearly as possible, while retaining the directness of the interview. Since my interviews are intellectual portraits that I hope explain how a person thinks, it seemed the most thorough way of doing it.

I think Hari is mistaken to claim his interviews are "intellectual portraits", because that gives him an artistic licence to write up an interview in the same way as Lucien Freud might paint the Queen. A newspaper interview should be a fairly straightforward and truthful account of an encounter -- it's not a profile, and if it is, it should be billed as such. And if Hari wants to include his subject's words from other sources, then it's very easy to stitch them in without losing any immediacy.

I was wrong to make up my quotes all those years ago, and Hari is wrong to make up his quotes today. The problem is, Hari is playing a bigger game than I was when a junior writer on the Times many years ago -- he is very high profile and he has even won prizes. He shouldn't play fast and loose with quotes, and neither, if an unpublished letter from Rowan Wilson to the Independent is correct (I'll leave you to Google that one), should he make things up. That letter is particularly damning.

We are all guilty of using licence, but to rely on it to the extent that Hari has done is to cross over into the world of invention. We have to draw these lines somewhere, and Hari must surely know, in his heart, that he has stepped over where most of us "content providers" mark that boundary. He should apologise to his readers.