There was a controversy a few months ago of major significance for all involved in the writing, ghostwriting or publishing of nonfiction books. The US author Naomi Wolf was taken to task for some historical errors in her book Outrages: Sex, Censorship and the Criminalization of Love, on the persecution of gay men in 19^th Century Britain. Sex between men was criminalized – indeed, it was not decriminalized until the 1960s. Almost unbelievably for a modern, liberal mind, in the 19^th Century it could carry the death sentence.

Unfortunately, Ms Wolf misunderstood an archaic legal term used in Victorian British courts. ‘Death recorded’ meant a commuted sentence and was the norm in these cases; the death penalty was not actually carried out, so her case that dozens of gay men had been executed did not stand up. More seriously, in one case she either made an error in research or omitted to point out that the individual involved, Thomas Silver, was prosecuted for a serious sexual assault on a boy of just six years old, not consenting sex with another adult. The only press report of the time described the details of the crime as being not fit for publication. The sentence that Silver – who was only a teenager himself – actually received was two and a half years’ imprisonment followed by parole. The jury recommended mercy on account of Silver’s youth. It was probably similar to the sentence such an offender would receive today.

The revelation that moralizing Victorian legislation simultaneously persecuted gay men and protected children from abuse is the kind of contradictory finding that undermines a good polemic.

If Wolf’s case is that gay men wanting to have a consenting adult relationship were persecuted and suffered under Victorian morality laws, it is certain that her story holds. Eminent barrister Helena Kennedy, writing in her defence, made the telling point that, while the death sentence was routinely commuted in cases of consenting gay sex, it still hung over the individuals, who subsequently lived their lives in fear. She corrected Matthew Sweet, who had alerted Ms Wolf to her original errors, over a mistake that he himself made by claiming that ‘death recorded’ was the ‘opposite’ of a death sentence – it most certainly was not. The story from the last century of computer pioneer Alan Turing, hounded to his suicide by this oppressive legislation, is well known.

In a separate recent controversy, concern has been raised by some historians over historical accuracy, or otherwise, of some novels set in the Nazi era. With fiction based on historical events, there is usually some licence for imagination and interpretation, but I would argue not when it comes to the Holocaust.

It is always essential to get your facts right. This is ultimately the responsibility of the named author, but a good ghostwriter, often with a journalistic background, can help you with this. We know the importance of checking the original documents: court reports, independent inquiries and so on. We read the full text, not just the quotes by a spokesperson or the executive summary.

The Wolf case does raise a fundamental issue for all authors of nonfiction: at what point does the story become a different one if the supporting evidence does not support it as clearly as one imagined? If too many facts change, the story changes. Personally, I think her story stands, but she should have taken more care with the cases presented. If you have a strong case, on a potentially controversial matter, every factual error is a chink in your armour.

• Philip Whiteley is a journalist, ghostwriter, novelist, and a founder member of United Ghostwriters, www.pjwhiteley.com