We all know him. He’s only 3 years old, but he’s the most important person in his family. If you encounter the Little Emperor at mealtimes, you may be surprised that he is fed before anyone else. He will probably refuse to eat what is put in front of him but will help himself to anything he fancies from his parents’ plates and would do the same from his siblings’ helpings, too, if they didn’t guard them fiercely. He uses his spoon and fork not to convey food to his mouth, but to bang repeatedly on the table, making such a din that no one can hear themselves speak.

He leaves the table when he feels like it but stays in the room interrupting adult conversations, climbing on to adult laps, wiping sticky fingers and/or a runny nose on their clothes. His parents hang on to every word he utters. He is so clever, so funny, the apple of their eye.

Love is, for many parents, if not blind, short-sighted. I know I was guilty of thinking my children charming, clever and amusingly precocious when, in fact, they were (occasionally) boring and boorish. Today it is the rule rather than the exception for parents, who invest their hopes and their prosperity in their children, to be blissfully unaware that they are spoiling them. A spoilt child can become a tyrant and an emotional blackmailer.

Recently, I encountered a fine specimen of the Little Emperor on the Tube. The train was crowded. When two women got on with a small boy and a folded buggy, a young man got up to offer his seat to the older woman. The little boy clambered up.

“Don’t you want to sit on Nana’s lap?” “No,” he replied, grabbing the Twix bar offered by Nana. For the rest of the journey he sprawled on the seat while his mother and grandmother, and other elderly women, stood.

Indulgent parents are doing their ewe lamb no favours. The discovery at school and in the playground that he is not the centre of the universe will come as a nasty shock.

If you are a parent or grandparent, try looking at the child’s position in the family from the viewpoint of an outsider and, if you don’t like what you see, start a gentle campaign for good manners and consideration.

If you are an outsider, have the courage to deal with the problem directly: tell the child to be quiet when grown-ups are talking. You may be afraid of putting your friendship with his parents in jeopardy and perhaps they will be offended, initially, but most children respond well to being told off by an outsider — the element of surprise pays off — and their parents, who can be remarkably timid about exercising their authority, will be relieved that you’ve done what they didn’t dare to do.

Do have a tricky family member you would like some advice on? E-mail Jane at body&soul@thetimes.co.uk or see her website, www.goodgranny.com. She cannot enter into private communication with readers

NEXT WEEK: The Over-Sexy Sister-in-Law