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 has been the charity's patron since 2005. “I cannot, after one night, even begin to imagine what it must be like to sleep rough on London's streets night after night,” William said Tuesday. “Poverty, mental illness, drug and alcohol dependancy and family breakdown cause people to become homeless.” In a post to the charity's Web site, Obakin said they found a secluded spot — behind some garbage bins — and settled in for a restless night. “But there was no shielding from the bitter cold, or the hard concrete floor, or the fear of being accosted by drug dealers, pimps or those out to give homeless people a ‘good' kicking,” Obakin said.