It's Wednesday so it must be time for Pointless Pedantry Hour. Strap yourselves in.
There was a bit on the Today programme earlier in the week (or it might have been on Start The Week, I can't remember) about the dear old Queen's Diamond Jubilee this year. The presenter went on to say that this was only the second Diamond Jubilee year in British history, the other being wacky old Queen Victoria's in 1897.
Now I am not a constitutional monarchy expert, as you know, in fact I'm more of a "first up against the wall come the revolution" kind of guy, but this struck me as surely incorrect. Stay with me and I'll explain.
Here's the thing: either 2012 is a Diamond Jubilee year by virtue of being a year that, when it started, was scheduled to contain the date of the 60th anniversary of the current monarch's accession to the throne, in which case it will remain a Diamond Jubilee year even if the Queen dies before February 6th, or it isn't a Diamond Jubilee year at all yet, but it will be once we've got to February 6th without the Queen buying the farm (and I reluctantly concede that I know of no reason to think she is in any immediate danger of checking out). Or, I suppose, we could say, as a third option: it is a Diamond Jubilee year, but it could retrospectively be declared not one if the Queen should be shot by Prince Philip in a hunting accident or randomly murdered and concealed in a shallow grave on the Sandringham estate (not necessarily by Prince Philip, but who knows) in the next month or so.
Anyway, either way, by most of those definitions 1820 was a Diamond Jubilee year as well, being the year that, when it started, was scheduled to contain (on October 25th) the 60th anniversary of the accession of George III. This never actually happened, as George (who was thoroughly deaf, blind and mad by this time) died on January 29th, but the exact same radio bit could have been done on January 10th 1820, if things like radio had been invented then.