Danny Alexander recounted in the Diary last week his daughter’s efforts in making unicorn poop. This is something of a historic marker. Most members of the cabinet in previous generations have been unforthcoming on faecal matters, particularly when it comes to comestibles.

In other countries there is less reticence. In Catalonia, Christmas isn’t Christmas without the Caga Tió, a log that is encouraged to defecate sweetmeats by being hit with a stick during the singing of a traditional song. ‘Shit, log, shit turrón, hazelnuts and cream cheese,’ it goes. ‘If you don’t shit well, I’ll give you a whack with the stick.’ This seems a good metaphor for Treasury attitudes to taxpayers. When the Independent ran an article last year about Christmas customs round the world, it explained the Caga Tió in terms of poo. It seems to me that poo and poop liberate public discussion of scatological matters in much the same way as bonking enabled the middle classes to read about carnal encounters in their newspapers in the 1980s without feeling that they had breached verbal taboos.

It is something of a surprise that the Oxford English Dictionary does not record poo in the excremental sense from any date earlier than 1960, and that none of its citations are other than Australian or American before this century. Perhaps in earlier times the word was regarded as slang that fell outside the main dictionary’s catchment. An interjection pooh was in use in the 16th century, but only in contexts expressing disgust did it edge into the stercoral semantic field.

Mr Alexander’s poop has a better established pedigree. In 1736, Nathan Bailey was geographically and acoustically specific in defining the verb: ‘To break Wind backwards softly.’ There were centuries of pooping like a horn (as in Chaucer), so I don’t think we need resort to the Low Dutch for the origin of windy pooping. By the 19th century, the nursery had deployed the term for more solid offerings, whether of unicorns or doggies. In the nursery it stayed until my husband’s medical colleagues extended juvenile vocabulary for the easier discussion of delicate subjects with patients. Pee and poo are par now, and we’re ready for the ‘Great British Poop Off’.