A nude photograph of a pre-fame Madonna is estimated to fetch around £10,000 at an auction next month, Christie’s announced this week.  The shot came about when, in 1979, Madonna replied to a newspaper advert by American photographer Lee Friedlander. “This picture is probably the most explicit shot taken,”  commented Matthieu Hummery, head of Christie’s photography department.  Thankfully, these days Madonna’s is more accustomed to posing in a leotard than in her birthday suit.