German artist Katharina Fritsch's idea of a huge cockerel in ultramarine blue is aimed at injecting colour into the square.

BBC: Trafalgar Square fourth plinth candidates unveiled

More aptly chosen is a second sunflower image of 1887 from the Metropolitan Museum of Art, depicting two slightly wilted blossoms lying on a rich ultramarine blue tablecloth.

WSJ: Vincent Van Gogh Up Close | Philadelphia Museum of Art | A Matter of Perspective | By Jonathan Lopez