'I’m worried about my dog. Dyson is now 12 – nearly 13 - which isn’t a bad age for a Labrador. Over the past few months he has started to struggle. He loves his food, and he loves the idea of chasing a tennis ball and going for a walk. However, all too often he will come back from a walk struggling with a limp. And he does seem to get exhausted much quicker than he used to. Are we being cruel and selfish in keeping him going? Is it time for him to be put to sleep? Isn’t it fascinating how a question like that has become the norm? So what is the risk that this could become the norm for humans too? One day might my children and grandchildren have a discussion about whether it is cruel to keep me going, or if it is now time to have me "put to sleep"? I’m not being facetious. I’m not equating a human life with a dog’s life. What I am doing is noticing just how easily a concept like being "put to sleep" can become the unremarked norm. Is that what we really want?'