I was in the bath. Generally I prefer to shower but we have a water-pressure problem at the moment which makes it difficult to maintain a constant temperature.

In order to wash my hair (what's left of it), I have to drop my head under the water. Now given that lying back is the easiest way to achieve this and given that we have a relatively short bath, I have to proceed by placing my hands along the sides of the bath to take the weight of my body. I then slide my bottom forwards causing a backwards rotation about the axis of my shoulders and thereby dipping my head under the water.

At this point, I let go of the sides and my back comes to rest on the floor of my bath and I raise my hands to my head to massage my hair in the appropriate manner, little realising that the bow-wave caused by the forward motion of my bottom during my descent has now reflected off the tap-end of the bath and is about to crash into me.

Water, of course, is very heavy and even this relatively small quantity is enough to cause my whole body to slide two inches towards the head-end of the bath. The only thing that could have saved my back from chafing would have been to have still had hold of the sides but no: my hands were already about the business of washing my hair.

Well, the injury was slight. I count myself lucky to have gotten away so lightly but in future, I can assure you, I won't be letting go of the bath until my bottom bow-wave has done its work and dissapated.