Anyone can dress up as Father Christmas, all it takes is a red suit and a white beard.
But should you trust him? We might be well advised to be cautious, as comedian Arthur Smith discovers when he meets the shadowy organisation called Santacon.
Every December, for the last 10 years, people have been taking to the streets of cities in large numbers - from San Francisco to Tokyo - dressed as Father Christmas, using the festive spirit and the benign appearance of Santa Claus to run riot.
Arthur Smith dons a fake beard and goes under cover to find out the mysteries of these massing Santas.