Last week’s art auctions in New York took in $186 million and set numerous records. “The record price that resonated most was for a joke painting by Canadian artist Richard Prince, which was bought by a young American hedge-fund manager for $747,000, four times its estimate. On a stark grey canvas, the artist has painted the words from a cracker joke: “I never had a penny to my name. So I changed my name.” With prices like this, contemporary art cannot be a joke – surely.”