It’s always interesting to read of the gifts exchanged by world leaders at their official meetings. Famously, when Barack Obama met Gordon Brown in 2009, he presented him with a set of classic movie DVDs, in response to Brown’s more thoughtful gift of an ornamental pen holder made from the timbers of the Victorian anti-slave ship HMS Gannet. After the media stir Obama’s perceived snub to Brown received, David Cameron must have thought long and hard before deciding on his gift for his meeting with Obama this week. So what did he end up getting? A piece of grafitti art, naturally.