So there is a very real hope that the 21st UN Climate Change Conference (COP 21), which starts on Monday, will be the last. Either Prince Charles and Dame Vivienne will prevail, and COP 21 will rescue Mother Earth from destruction by agreeing worldwide legally binding carbon emission restraints; or they won’t, and then, by their own logic, it will be too late for any international conference to do anything ever again, so they might as well shut up. For those of a more sceptical cast of mind, there is a third possibility, which is that the Prince and the dressmaker will fail, no legally binding targets will be agreed, and the world will go on very much as before. I would bet His Royal Highness an enormous amount of money on this last outcome, secure in the knowledge that, if I am wrong, I will not be around to pay out, but if he is wrong, he will be.