When she formally opened the Victoria line in 1969, the Queen became the first reigning monarch to ride on the London Underground. Other suggested names included the Viking line .
Down Street underground station closed in the 1930s; it then became a base of strategic importance in World War II before closing for good - or at least until now..
A new book aims to showcase the best of the London Underground stations built from the mid-1920s until the Second World War in a style described as Medieval Modernism .