Julian began his career working with Edward Cullinan (1969-72). He joined the teaching staff at the Royal College of Art under Sir Hugh Casson in 1972, and became director of the Royal College of Art Project Office (1973-79). In 1979 he joined Arup Associates. He set up his own practice in 1983.
His early career was concerned with the modification, alteration and restoration of existing buildings, many of them of considerable historic importance. Since establishing his own practice he has been increasingly involved in the design and construction of new buildings, in which the lessons of history are combined with contemporary architectural thinking and technology.