"Works by Banksy and other graffiti painters failed to sell in London today as buyers stayed away from an auction of contemporary and urban art. Less than a third of the 270 lots found buyers at Lyon & Turnbull's sale, which was the latest gauge of demand for street art after prices surged to records in the last three years. Dealers said demand, reduced by worries about the economy and confusion about the authentication of Banksy's pictures, may be an ominous sign for the mainstream art market." [Bloomberg]

Or maybe it was just because Pest Control, Banksy's official authentication agency, refused to give its stamp of approval on a number of the items. And art collectors willing to drop five and six figures on a work sort of like having the peace of mind that they're purchasing something authentic.