There's a whole compendium of jokes – most of them in questionable taste – about the doctor who tells his patient he's got some good news and some bad news.
For instance, the good news is that you've only got a day to live, and the bad news is that I should have told you yesterday.
Or, the bad news is that we're going to have to amputate your legs, and the good news is that the man in the next bed wants to buy your slippers. I know. Pretty awful. But I repeat these gags not because I'm channelling Les Dawson, but because they relate to my own experience.
I had been taken into hospital and a doctor came to my bedside and did a version of the good news/bad news scenario. A scan had revealed I had cancer, he said, but fortunately it seemed to be restricted to my kidney. This meant that they could whip the kidney out (his words) and, with a bit of luck, I could lead a perfectly normal life thereafter.
It was exactly two years ago when I became mono-kidney man, and, at the risk of tempting fate, I have to say I have never felt better. I say this merely to add my own personal testimony to the newly launched campaign, reported in yesterday's i, to get people to donate a kidney, in a similar way as they would give blood.
The charity Give a Kidney – One's Enough found a substantial degree of ignorance among the general public about kidney donation, with a third of British adults not even realising you could give your kidney to someone in need, and many believing there to be inherent risks in doing so.
It was in 2006 that the law changed to allow altruistic donations, but thus far only 88 people have done so. Around 300 people each year die for the lack of a kidney. These are not great statistics. Of course, it's not as straightforward as giving blood (I don't know what the equivalent of Tony Hancock's "Why, that's very nearly an armful" would be), but all I can say is that having a kidney that exists in splendid isolation has not thus far been an impediment to my enjoyment of life.
In fact, I was rather surprised when, after my operation, I asked the surgeon how I now needed to make radical alterations to my diet, for instance. "You don't need to change anything," he said. "Just carry on as normal." "You don't know what you're saying!" screamed my liver. "His idea of a quiet night is a bottle and a half of Chardonnay!" "Well, maybe cut down on the drinking," said the surgeon, miraculously responding to inner voices.
Anyway, the point is this: it doesn't curtail your life to have just one kidney, and it may just save someone else's.