Today is my seventieth birthday: as always, too near Christmas to make me want to celebrate in any elaborate way, but a small gathering of friends and family will be joining me over the weekend. It's commonplace for people to say they don't feel their age, and that's true of me too: I am as full of ideas, and of early morning eagerness to be at my desk, as ever, and I'm working as hard as ever, if you can call what I do work. But in another sense I am fully aware that a milestone has been reached. Seventy can't be called middle age. Seventy is old. Seventy is the beginning of the last phase of life. The effect this knowledge has on me is powerful, and in its way exciting: I feel that time is limited, and I must use it well. My ambition, always a great driver, has changed, though not lessened. I feel there is still time - just - to do my best work ever, and nothing else will do. In personal terms I find myself wanting to treasure every day that I have with those I love. In spiritual terms - and after all, for the first twenty years of my life I was a convinced believer in an afterlife - my goal is to make myself ready for death. That may seem premature, but I think it's going to take time. The instinct is to cling on at all costs. I want, when my time comes, to look back on my entire life with gratitude, not disappointment; and to release myself without regret.