Algorithms have long been able to produce basic news stories from press releases or sets of financial data; that is not much of a threat to most humans in the news business. Now, however, artificial intelligence (AI) has taken a step further. It has learnt to perform a tougher task - to produce convincing-looking fake news.

Stringing together a few formulaic passages from a set of numbers is a mechanical job. Inventing a fake news story on a random subject requires imagination; not every human is up to it.