Final answer:
Robert Smirke used the Neoclassical style in the design of the British Museum.
Step-by-step explanation:
Robert Smirke used the Neoclassical style in the design of the British Museum. Neoclassical architecture was characterized by its inspiration from ancient Greek and Roman architecture, with a focus on symmetry, order, and proportion. Smirke incorporated classical elements such as columns, pediments, and arches into the design of the museum, creating a grand and monumental appearance.