Innovations in material science, (nano) fabrication techniques, and availability of fast computers are rapidly changing the way we design and develop modern defence applications. When we want to reduce R&D and the related trial-and-error costs, virtual modelling and prototyping tools are valuable assets for design engineers. Some of the recent trends in computational electromagnetics are presented highlight the challenges and opportunities . Why researchers should equip themselves with the state-of-the-art tools with multiphysics and multiscale capabilities to design and develop modern defence applications are discussed.