When he was a young man, my dad skidded on black ice while driving his Jaguar SS sports car past the brickworks in Carluke. A front wheel collapsed and the car and my father ended up badly mangled. Fortunately, one of them survived, but only due to copious blood transfusions.

Since then, my wife, nephew and brother-in-law have all been helped and, indeed, in some cases saved, through receiving blood. As a consequence, I turn up to donate whenever I can. I’ve got a badge to say that I have done so lots of times. I wear it on my suit, and if anyone asks what it’s for, I tell them. I’m not sorry if this sounds showy or big-headed. If it inspires one person to donate and another 99 to think I’m a blaw, so be it. It’s worth it for the one person.

The last time I went, I got the friendliest, most attentive nurse I’ve ever met. Unfortunately, something happened involving the tube being caught and I ended up giving too much. That’s what I was told. How much was too much? An extra 25 millilitres. I tried not to laugh and was only partially successful. Twenty-five millilitres is around five per cent of the total donation.

I’ve been donating since I was 18, and at that time I was a skinny wee skelf who looked like a Chupa Chup lolly when I wore my crash helmet. If I could afford to give a standard donation in those featherweight days, then I can certainly give an extra few per cent now.

Understandably, the blood transfusion folk have to draw the line somewhere, so they fussed over me, gave me some extra juice and took both my blood pressure and my phone number. I went home, reassured by the maths.

I get reassured by maths and science quite a lot. Whenever I hear that an institution has improved dramatically while another is making only slow progress, I revisit the parable of the Reliant Robin and the Bugatti Veyron. The former is very slow and the latter capable of extraordinary speeds. But which one is best at improving its speed? If the Bugatti is within a mile per hour of its maximum and the Robin is pulling away from the traffic lights, it is the three-wheeler whose speed will improve most when the driver floors the accelerator.

You’d think that someone with this insight would have worked out that he should rehydrate the evening after donating an excess of blood. Instead, he tried to fix his wireless network, and woke up with a sair heid the next day.

Gregor Steele, Scottish Schools Equipment Research Centre.

Gregor Steele doesn’t like the way they do graphs on television.