Did you know, outrageous though it may sound, that a bunch of foreign judges have the right to order British judges not to sentence convicted criminals to being hanged, drawn and quartered, and then to have their corpses dragged through the streets, entrails spilling out, for the public to gawk at?
Did you also know that British judges can't even sentence the most heinous murderers of innocent children to be publicly beheaded, and then to have their heads displayed on Westminster Bridge till they rot? No, not even if both houses of parliament approve laws that say they should.
The reason is Article 3 of the European Convention on Human Rights, which says: "No one shall be subjected to torture or to inhuman or degrading treatment or punishment." And that, we learned this week, includes locking people up behind bars, throwing away the key, and telling them: "Sorry, chum, that's it. You're there till the day you die."
Ministers were shocked, I tell you, shocked. Mr Cameron said he "profoundly disagrees" with the ruling from Strasbourg. The justice secretary Chris Grayling said: "The British public will find this ruling intensely frustrating and hard to understand."
Here's what I find hard to understand: that a country that supposedly prides itself on its sense of justice is ruled by a government that has so little comprehension of what basic human rights involve that they are now talking, in all seriousness, of ripping up the UK's adherence to the European convention and going back to … well, who knows what they want to go back to?
Let's be absolutely clear about what those pesky foreign judges actually said: they didn't rule that murderers can't be sentenced to spend the rest of their life in jail, merely that there must, at some point, be an opportunity for a "whole-life" sentence to be reviewed, to give a prisoner just the tiniest of chances, just a smidgeon of hope, that one day he may regain his freedom.
That's how things stood until 2003, when the then home secretary (take a bow, David Blunkett) decided to scrap it. "It is the right of the British Parliament to determine the sentence of those who have committed [the most heinous] crimes," he said after this week's ruling. Including, presumably, if parliament so desires, the sort of sentences outlined above.
Nearly 30 years ago (August 1984), The Observer wrote in an editorial: "Which country has been found to be in contravention of the European convention on human rights more often than any other signatory? The shameful answer is the United Kingdom, which last week stood in the dock with head bowed for the eleventh time to hear the judges pronounce a verdict of guilty ... In the past decade, we have established ourselves as the worst protectors of human rights in western Europe."
I remember the words well, perhaps because I wrote them. But it's worth digging them out of the cuttings book just to remind ourselves that our abysmal record has nothing to do with the threat of jihadi terrorism or post-9/11 paranoia.
We just aren't very good at protecting human rights. And, to me at least, that's deeply shaming. All the more so, given that the man who played a leading role in drafting the European human rights convention was a British Conservative politician, Sir David Maxwell-Fyfe, who served as home secretary, attorney-general, and Lord Chancellor, as well as being a prosecutor at the Nuremberg war crimes trials.
So we're going backwards. Where once a leading British jurist was instrumental in drawing up a code of basic human rights, now his successors blithely talk of tearing it up. They think nothing of lambasting foreign dictators for locking up their opponents without putting them on trial (Abu Qatada, anyone?); they condemn regimes that use torture and extra-judicial detention to silence "enemies of the state" (extraordinary rendition, anyone?), and they happily lecture all and sundry on the importance of an independent judiciary and open justice.
I can't help wondering what they see when they look in the mirror every morning.
Incidentally, I'll be completing my 184-mile walk along the length of the River Thames within the next few days, so the last of my audio slideshows should be on YouTube by this time next week. You'll find them here.