To unite the Commissioner of Irish Lights existing engineering facilities with a new head office, to include technical and administrative functions, at its highly prominent harbour site in Dun Laoghaire. The site for the development was particularly sensitive being within Dun Laoghaire Harbour and in close proximity to a number of Protected Structures such as the adjoining yacht clubs and the harbour itself. The client is a statutory government body operating and maintaining the most technologically advanced Aids to Navigation around Ireland?s coastline. A conscious decision was made at an early stage to design a landmark modern structure, reflecting the ethos of the client, and also to provide a counterpoint to the various historic structures nearby, themselves prominent landmark buildings. The complex design challenge evolved into a development in two halves: a circular open plan administrative office building and a rectilinear workshop building. The form of the two main structures derived not only from a study of the internal processes being incorporated, but also from the requirement to provide sustainable and future adaptive accommodation. The striking contrast of these two forms leads to a dynamic landmark architectural solution befitting the site and a progressive client. The enclosing fa?ade is a sophisticated glazed twin-wall system, maximising natural light, panoramic views both out from, and into, the building and yet providing sustainable environmental control over the internal office space. A distinctive central lantern provides abundant natural light into the building?s core and the photovoltaic panels that skirt the recessed second floor level, nod politely, to the highly evolved functional navigational aids that the client is responsible for.