But the hockey stick, on which Mann’s reputation largely rests, was and is a nonsense. It obliterates the medieval warm period; it is unduly reliant on proxy data — bristlecone pine samples — which are known to be unreliable; it is dependent on a flawed algorithm which, according to every statistical authority who has ever looked at the subject, creates the same hockey-stick data almost regardless of the information you feed into it.

Surely if you’re going to sue someone for defamation, this must involve an examination of the reputation said to be worth defending. What would this say about Mann, onlie begetter of arguably the most comprehensively discredited artefact in recent climate science history?

And if Mann’s scientific reputation really matters to him so much, maybe he ought first to do a bit of reading on how world-class scientists actually behave. He could do worse than read Paul Johnson’s account in Modern Times of how Einstein proposed his general theory of relativity. Einstein insisted that before his claims were taken seriously, they must first be verified by empirical observation, in the form of three specific tests. Of the final one — the red shift — Einstein wrote: ‘If it were proved that this effect does not exist in nature then the whole theory would have to be abandoned.’