LONDON: A cold alley in central London is a far cry from a palace — but it was the spot Prince William chose to sleep to highlight the plight of homeless British teenagers. He spent a chilly night near Blackfriars Bridge last week with Seyi Obakin, the chief executive of British homeless charity Centrepoint. William is the charity’s patron. A photograph released by the charity shows William, 27, in the alley in jeans and a gray hooded sweatshirt. In a post to the charity’s Web site on Tuesday, Obakin said they slept on cardboard boxes in an alleyway. He said temperatures that night fell to 4 degrees Celsius.