I have been drawing a caricature of The Revd Richard Coles, to be published with a review of his autobiography, in which he tells the story of his transformation from pop star to Britain's favourite vicar.

Some people are easier to draw than others and Richard took several versions before I was satisfied, and I am still not entirely.

A caricature is made up of three elements. There are those physical characteristics that come through genes. The shape of the face, colour of skin etc all inherited from parents and ancestors. Getting those things right is essential to finding a likeness in the drawing.

Next there are the acquired characteristics that tell something of the person’s life; a publican’s ruddy complexion, the glutton’s hanging gut, or a rugby player’s broken nose are obvious examples. And aside from the obvious ones there are many small, subtle give-aways for the cartoonist to look out for.

Finally there are the vanities. These are the points the caricaturist can legitimately ridicule.  Traditionally cartoonists did not play up disability. During the Second World War the American President Roosevelt, who was a wheel-chair user, was never shown other than standing tall, even by cartoonists of a different political persuasion. But vanities hairstyles, choice of clothes, even glasses (now as much a fashion statement as a means to improve eye sight) are all there to be used, pointed up and exaggerated for satirical effect.

Drawing Richard, one of the hardest things was getting the key physical characteristic right – the prominent and distinctive nose. It is not a straight-forward roman or aquiline nose, but one in a sub category of its own. Its prominence has to be carefully blended with its thin shape and sharp nostrils, for the angle and shape of his nose utterly defines his face. It can also be used as a device to say something about his wordly success and confidence.

The vanities were no problem – the cassock, the dachshund (a reference to dogging was essential); the poise, stance and tendency to middle-aged stoutness said much about his life-style.

This is what I came up with.