I saw mummy kissing Santa Claus, underneath the mistletoe last night...

Now, unless mummy has a fetish for fat older blokes with questionable sartorial tastes, this song lays bare one of the greatest betrayals of a child's life. The moment when a youngster discovers that Father Christmas doesn't live in the North Pole overseeing toy production all year long, before heading off on one wild round-the world sleigh-ride each Christmas Eve.

All those letters posted to him over the years? A waste of time. Being naughty or nice? No-one noticed. There are no elves, no flying reindeer, and Father Christmas is actually... your dad.

So, why do we put them through it? Are we actually lying to our kids or are we really only encouraging a sense of wonder? There's nothing wrong in that, surely, allowing kids to develop their imaginations?

Some parents go so far as to leave muddy footprints near the fireplace, and tracks in the snow where they're lucky enough to have Christmas Day snowfalls. Others sprinkle 'reindeer food' in the garden the night before (muesli mixed with glitter, available at Christmas fairs at hugely inflated prices). In the normal course of events, this is a level of subterfuge employed only by criminals, and not very good ones at that. But the overall effect can be quite magical...

So, this week's talking point: is Father Christmas a healthy white lie, or a nasty cruel deceit?

• As spending and consumerism spirals ever upwards, isn't it time to put St Nicholas to bed... for good?

• What elaborate ruses were (are!) contrived by your parents to convince you of Santa's existence?

• Are we teaching our children that it's OK to believe in a false reality? Isn't this exactly what makes some societies dangerous - a mass denial of the blindingly obvious truth?

• However, developing the imagination and encouraging dreams can't be such a bad thing. Rather, as we get older, we realise there's much to be said for have a rich imaginative life. Does the 'white lie' of Santa Claus actually develop a healthy sense of wonder early on and is therefore a very good thing?

• What do you say when your child asks you, does Santa really exist?

• At what age is it right to let children in on the truth about Father Christmas? What's the best way to let them down gently?
  

• Do you remember when you found out the truth about Father Christmas?

• What are your happy memories of believing in Santa? Did you actually see him, hear the bells on his sleigh at night flying overhead? What are the other arguments in favour of the Father Christmas myth?