Most of the world is familiar with the international standard sizes for paper. Letters are usually written on A4-size paper (210mm by 297mm). Magazines tend to have the same dimensions. And leaflets are frequently A4 sheets either folded in three (201mm x 99mm) or made into A5 booklets (210mm by 148mm).

(These observations do not, of course, apply to the United States of America, which has persistently failed to adopt the international standards that almost every other nation has embraced.)

But when it come to bog paper, there seems to be no international standard sizes — although in few countries, such as Germany, manufacturers have settled on sheets of format A6 (148mm by 105mm). The bumwipe we normally use in my own household (Costco’s Kirkland Signature, if you must know) has sheets measuring 125mm by 110mm. Other UK brands for domestic use have similar dimensions: for example, Andrex has an average sheet size of 124mm x 104mm, while Sainsbury’s own brand seems to be a fraction larger at 125mm x 105mm.

But here’s the crazy thing. What really puzzles me is that many British public bogs offer us sheets of toilet paper of weird dimensions. It is not unusual to find that the loo rolls are perforated to provide sheets that are more than three times the length of the typical domestic product. In the interest of scientific research, I recently liberated a length of bog roll from a local shopping centre and found that each sheet was a mere 90mm wide but more than 390mm long. (For those who only understand US Customary Units, that is just three-and-a-half inches wide but fifteen-and-a-half inches long.)

Please, someone, tell me why! Who needs to wipe their bum with sheets so long and so narrow?