It took snow in London for me to know there's such a thing as "the etiquitte of snowball fights"

The etiquette of snowball fights
With swathes of Britain covered in snow this week innocent folk have found themselves the unwitting targets of snowball attacks launched by grinning children. But how to react, asks Brendan O'Neill?

When police in Hertfordshire warned children that throwing snowballs in an "irresponsible way" could face arrest or a fine, they were branded "winter killjoys". Yet one man certainly struggled to see the funny side after his van was pelted by a snow-wielding gang of children near Alexandra Palace in London. He pulled out a Stanley knife to frighten his woolly-gloved assailants away.

So what is the proper snowballing etiquette? Is it acceptable for children to lob snowballs at adults, including perfect strangers? And should the chucking of a snowball ever become a police matter?