It's cruel to mock, thrillingly so, and sometimes you can't resist.

Here, from the BBC Religion message boards, is quite the most imaginative refutation of evolution I've ever read.

For many years I have been handling UK £10 Notes. These have throughout had an impress of Charles Darwin (1809 - 1882). Over this same very long period. I have methodically and carefully observed that Charles has not changed (evolved) even one tiny bit. This, I submit, having been scientifically undertaken, can be taken as irrefutable evidence that the Theory of Evolution is, in fact, what it is shown to be - False!

This must truly be taken to be the last 'last word' on "Evolution versus Creationism."

Thanks for that, glorybe21. It is indeed the last word on the subject, at least until I catch my breath. It's been three hours now, and I think I've nearly caught it.

OK, here we go. Anyone easily wearied by repetitive explanations of the bleeding obvious may choose to look away now.

Natural selection works like this. Every biological entity, whether plant, animal or other, has a genetic code, stored as a double helix molecule known as DNA. This code is like a blueprint, or perhaps rather more like a computer program, for the construction of the entity. It's actually slightly different in the case of viruses, but we'll leave that aside for the purposes of this discussion.

When the entity reproduces, its code is passed down to the next generation. In the case of single celled organisms such as bacteria, a cell simply splits, and both new cells have the original code. In the case of sexual reproduction (animals and plants), excluding exceptions such as hermaphrodites, a male mates with a female, and they each provide one helix of the DNA.

Now, in order to reproduce an entity has to survive to adulthood, find a partner in the case of sexual reproduction, etc. The more suited an animal is to its environment, the more copies of itself it can make. The next generation is subject to the same pressures. Unfit code, ie code which generates entities which are unable to reproduce, will be eliminated. Over the generations, bad designs will be sifted out like lumpy flour, and only the good, fine-grained designs will remain. For a code, good/bad is defined simply as fitted/unfitted to make many copies of itself.

Changes are introduced to the code through mutation. Every now and again, an error occurs when the code is being copied. The vast majority of these changes are harmful, and are eliminated. Some are neither harmful nor advantageous, and may or may not thrive according to random chance. A few, though, are genuine improvements, and these are more likely to survive.

The Darwin tenners are not an example of this process. Firstly, there is no competition between tenners. Secondly and most importantly, tenners are not made by copying each new tenner from the previous one. Instead, the original design is printed out millions of times, from the same template. Therefore, and this is the bit where the sledgehammer finally cracks the nutjob, therefore the fact that Darwin's picture has not "evolved" does not in itself refute the theory of evolution.

Sorry to put you all through that. I would never say this to my students, but honestly, if you didn't already know that you must be a bit thick.