Once this scandal has been properly brought out into the open, it will raise the most disturbing question mark yet over the promotion of the greatest and costliest scare story the world has ever known.

Two years ago last week, I wrote a column given the provocative heading “The fiddling of temperature data is the biggest science scandal ever”. It was the second of two articles which attracted a record 42,000 comments from all over the world, reporting on the discovery by expert bloggers in half a dozen countries – led in Britain by Paul Homewood on his site “Not a lot of people know that” – that something very odd appeared to have been done to the official land surface temperature records on which, more than anything else, the entire alarm over man-made global warming has rested.

These derive from the record known as the Global Historical Climatology Network (GHCN), run by the US government’s National Oceanic and Atmospheric Administration (NOAA). By comparing archived data with that now being published, the bloggers claimed to have discovered that temperature records all over the world had, seemingly, been systematically “adjusted” to show older temperatures lower than those originally measured and more recent temperatures higher than those recorded: thus conveying the notion that the world is warming significantly more than the actual data justified.

This scandal has now surfaced again with accusations made by Dr John Bates, a recently retired senior scientist at the NOAA, against his former boss , Tom Karl. Bates alleges that an NOAA paper written before the historic climate conference in Paris in 2015 breached its own rules and was based on misleading and unverified data. That, to many, looks like the paper was designed to stoke up hysteria over global warming in the run-up to the conference.