Created by Horace Walpole in the 18th century, the house is one the finest examples of Georgian Gothic revival architecture. It's recently undergone a major restoration and the internal rooms are gradually being opened to the public as they are restored. There isn't much furniture as it was all sold off, but the architectural details are just wonderful.
The whole thing reminded me so strongly of the Gothick Gatehouse dollshouse that used to be available, which featured the same trefoil windows and Sue Cook gothic details. I wonder if this house was their inspiration?
