Do not ask. Why does loo paper need to be strong anyway? So that a puppy can run around a stripped-pine, sunlit interior without it falling to bits, that's why. But now Procter & Gamble admits to having gone too far. Its Charmin product is not blocking the nation's sewage system. Of course not, perish the thought. But if all loo paper had enough "temporary wet strength" to enable people to use it to escape from tall buildings in the rain, then the drains might back up. So P&G have made it less strong - a change that will no doubt be advertised with a fluorescent flash on the packet: "New. Improved. Weaker."

Do not ask. Why does loo paper need to be strong anyway? So that a puppy can run around a stripped-pine, sunlit interior without it falling to bits, that's why. But now Procter & Gamble admits to having gone too far. Its Charmin product is not blocking the nation's sewage system. Of course not, perish the thought. But if all loo paper had enough "temporary wet strength" to enable people to use it to escape from tall buildings in the rain, then the drains might back up. So P&G have made it less strong - a change that will no doubt be advertised with a fluorescent flash on the packet: "New. Improved. Weaker."

The development of lavatorial hygiene from the days of Izal, the hard, waxy sheets that came in a box, offers an important commentary on our society. PhD theses are no doubt being written about the significance of the obsession with strength, or of folding a V-shape in the end of the roll or of choosing quilted brands. One of them, at least, will be entitled: "U and non-U bend: lavatorial clues to socio-economic status".

When television advertising started, people doubted that loo paper could be done. They reckoned without "temporary wet strength". If only they had known where it would lead.