Swimming is one of the best forms of exercise, provided you follow these simple safety rules:

• NEVER SWIM IN A LAKE OR RIVER These contain snapping turtles, which have no natural enemies and therefore grow to the size of motel units, plus they tend to be irritable because they mate for life. Lakes also contain giant lake-dwelling carp, which will watch you from the gloomy depths with their buggy eyes, wondering with their tiny carp brains whether you would fit into their mouths.

• NEVER SWIM IN THE OCEAN The ocean contains creatures that make the giant lake-dwelling carp look like Banbi

• NEVER SWIM IN A SWIMMING POOL People say that people pee in swimming pools. You may not be peeing in swimming pools, but some people do, which promotes the growth of bacteria, which is why swimming pool owners are always dumping in toxic chemicals, to the point where there is virtually no actual water in the pool, just toxic chemicals and dead bacteria and old pee. This is why, as you may have noticed, the actual owner never gets into the pool. He's always off pretending he has to do something important involving the filter.