The shock of returning from a summer holiday has dissipated, and half-term is just around the corner. Now October heralds the conker season, when short-trousered youngsters kick through piles of sticky leaves or throw sticks at the branches to dislodge and plunder the fruit of horse chestnut trees. They thread them with a shoelace or piece of string, then smash them against each other in a playground ritual dating back aeons. By late October, the tarmac playground is full of smashed dark brown conker shells, their hard magnolia pulp sprinkled over the mush of fallen leaves. Any prized conkers still intact have bizarre values: 'a tenner', 'a 50er', 'a tunner' (100). The value comes from the combined value of the conkers they had triumphed over, usually achieved by smashing them off their string. The 42nd annual world championships took place recently, attracting 300 players from around the world. A Londoner won. Even so, adults are lamenting the fact that too few children these days are playing the 'sport'. The reasons are legion. The conker season is too short to hook youngsters who are addicted all year round to the internet, PlayStations and video games. More worryingly, the conkers are becoming thin on the ground, and on the branches, especially in London - largely due to global warming. Britain's 470,000-odd horse chestnut trees have been badly weakened by various scourges, including record summer temperatures and drought. They have also been hit by a virulent, largely untreatable disease, 'bloody canker', and the rise of pests like the leaf miner moth. Now, one in 10 trees is failing even to bud its flowers, and therefore produce nuts. Many more have produced smaller, weaker conkers. The nanny state is also to blame. Some London councils have picked the conkers from trees to prevent children from throwing sticks to dislodge them, for fear they'll damage nearby properties. One head teacher last year forced children to wear goggles while playing conkers, to save them from flying debris - and, more likely, save the school from personal injury lawsuits. In my conkering heyday, teachers helped and there were no personal-injury lawsuits. In 1977, I had a '145er', the king conker of Mayfield Middle School. Until, that is, new girl Audrey Adams destroyed it in one fell swoop with her 65er - a half-flat nut with a sharp edge. (Well, she didn't destroy it, per se: she hit my hand, I dropped the conker, someone shouted 'stampsies' and 60 pairs of feet rushed to crush my fallen champion). It took two teachers to rule that Audrey hadn't cheated, by soaking her conker in vinegar, drying it in a drawer for a year or baking it hard in the oven. Distraught, I cried through French. It would be a crying shame if no one else could play conkers again.