I’m on holiday with the family in Northumberland this week, and today we were in Alnwick (pronounced “Annick”, in case you’re relating this story and you want to sound knowledgeable). The castle here had a starring role in the Harry Potter films as Hogwarts School, but far more interesting than the castle itself are its magnificent gardens.

One garden, which can be seen only as part of a guided tour, is particularly fascinating – the Poison Garden. Every plant in this garden can in some way be used as a poison. Garden plants such as foxgloves (digitalis) and the seemingly-harmless daffodils (it’s the bulbs – deadly) are included as are opium poppies and cannabis. However, more traditionally poisonous plants are also present including deadly nightshade, wolfbane and, of course, hemlock.

Hemlock is the poison that Socrates was obliged to drink when sentenced to death. However, it was also reportedly used on the Greek island of Keos (now Kea) to carry out senicide. As a result of a seige, so the story goes, the inhabitants of Keos voted that all those aged over 60 should commit suicide by drinking hemlock. In this light, the proposals to combat the public debt in Greece by raising the pension age look positively benign…