Four and a half years ago, Parnham House in Dorset was reduced by fire to a smouldering shell — a catastrophe followed by the arrest of its owner, Austrian banker Michael Treichl, for suspected arson, and his subsequent death by drowning in Lake Geneva. But what promises to be one of Britain's most daring and innovative architectural resurrections is now in hand thanks to the man dubbed 'the new Leonardo of design'. Thomas Heatherwick is the creator of the stunning cauldron at the 2012 London Olympics, as well as an array of buildings and bridges around the world. Parnham House in Dorset pictured before a devastating fire reduced it to a smouldering hell