One of the questions on the United Ghostwriters tweetchat on 20 January was whether a ghostwriter would ever turn down a project for which they were qualified, had the availability, and the fee was good. In other words, are there issues of principle that would prevent you from taking on a project?

So far in my ghostwriting career, I have been fortunate to have clients who I consider to be honest in the story they tell, and justified in telling it. On occasion, I have turned down offers to work on a book that promises to reveal the secrets of a lucrative and unconventional investment strategy – but where there is no registered company address, and there would be difficulty in carrying out due diligence. It is a case perhaps both of ethical principles and basic fear on my part! I wouldn’t want to be accused of peddling propaganda around what turns out to be a Ponzi scheme.

But there may be tough cases. People who have done some evil stuff in their careers will not want to come across as evil in their memoirs, and perhaps they have done some good also – the careers of certain politicians come to mind. Perhaps there is someone out of prison, claiming that the trial was unfair, or who are turning their life around, and they want to restore their reputation in a book. Those who have had a chequered life have the right to tell their story, and no one is an absolute saint.

And of course, there is the fear of poverty at the heart of many freelance writers. It is easy to turn down a questionable project if you have alternative offers, but if other work has dried up, your partner is unemployed, you have children, and the bills are mounting, the decision could be tough.

One way around the dilemma is to include a clause in the contract declaring that the ghostwriter will not consciously mislead the reader, nor help the client cover up wrongdoing. A reputable publisher will run legal checks on the copy, to ensure that there is nothing defamatory or otherwise seriously awry.

It is perfectly justifiable for the client to promote their achievements, and downplay their weaknesses. They will want more paragraphs on how they won a prestigious award than on the time they were arrested for drink-driving, and that’s fair enough. This is their story, after all. Ethical questions may arise if the ghostwriter is asked significantly to distort a significant passage of history. Of course, in between these two areas, there may be much territory that is in a shade of grey – and this is where contracts, legal checks and careful judgement come into play.

• Philip Whiteley is a full-time author, ghostwriter and journalist. His critically acclaimed fiction is written under the byline PJ Whiteley. www.pjwhiteley.com