Donald Insall Associates were appointed in 2004 to prepare a Conservation Plan for the entire Palace of Westminster buildings from the Sir Charles Barry and Augustus W Pugin period of re-construction in the mid 19th century. The study of the most significant Victorian building in the country, which also contains, with the Lord's Chamber the most significant Victorian interior, has been the largest conservation plan undertaken by the practice. The document involved: Research into the different factors which add to the building's significance Visual surveys of all accessible rooms and spaces both internally and externally Reviewing the issues which threaten the fabric of the building Preparing policies which aim to ensure the building's special interest is preserved, while allowing necessary changes.