Last year, a reader in fluid mechanics at UCL published a mathematical formula that can be used to predict the effects of time on the ink particles of a tattoo.

We all know that tattoos fade with time, although they do not disappear completely. Just as the skin it is trapped in ages, so does the tattoo. As the cells containing the ink particles die or are shed by the body, the colours of the design can gradually fade or change, while outlines can become blurred and less well-defined.

Intricate detailing tends to be affected first, while thicker lines resist for longer. Depending on how you look after your skin, this mathematical formula can provide you with a prediction of how fuzzy your tattoo will get. Tattooed skin that is exposed unprotected to the sun’s harmful rays is likely to degrade more quickly.

So what do you do if your tattoo started life as a beautiful and meaningful piece of body art, but has now been reduced to a bit of a blurred smear? Depending on the size of the tattoo, you could get it covered with another, although then, of course, the new one will degrade in the same way. Laser tattoo removal is surely the most aesthetic and effective way forward.