Blue is the favourite colour of most of us, but also of many artists, from Matisse to Yves Klein, via Picasso and his famous period. This is hardly surprising given that it is the colour of the sky and the sea, and therefore in a way the colour of freedom, of peace, of paradise. So in this week of "Blue Monday" we have gathered together the azure, navy or indigo works of our artists to celebrate our favourite colour. I'm blue dabadidabada...