David Pettifor was a theoretical physicist who changed the nature of materials science by raising the status of materials modelling to that of materials characterization and processing. He believed that the subject advanced through the development of simple models that withstood rigorous testing against experiments and the most accurate numerical computations. Having been a pioneer of total energy density functional theory calculations, he went on to derive analytic interatomic potentials for transition metals and nearly-free-electron metals and alloys from quantum mechanical principles. He is probably best known for the development of highly successful structure maps for binary and pseudo-binary alloys that were used by alloy developers in industry to create intermetallic alloys with improved properties. At Oxford he established the first materials modelling laboratory, bringing together physicists, chemists, materials scientists and engineers to model materials across length and time scales, which became a flagship laboratory for materials scientists world-wide.