Windsor Castle is the largest and most archaeologically complex secular building in the UK. It is a working Royal Palace, national monument and major visitor attraction. Miriam established the Conservation Plan framework for the castle and authored the chapter on the State Apartments, which have been the historic core of the castle since the twelfth century. The Conservation Plan sets out the evolution and significance of the building, detailing how that significance is vulnerable and opportunities to reveal or recover significance in the context of continued use. Miriam was also involved in detailed designs to extend access for visitors to the medieval heart of the castle.