Banksy's brilliant Christmas card creates a stir

A Christmas card from Banksy that was posted on Facebook last year has been causing a bit of a stir on Twitter in the past couple of days.

Of course, the anonymous street artist is no stranger to controversy, as this work called Slave Labour illustrates.

Controversy helps in the art world, especially with the selling price of works such as 'No Ball Games'.

And this one in New York.