Metamaterials are artificial materials with characteristics beyond those found in nature that unlock routes to material and device functionalities not available using conventional approaches. Their electromagnetic, acoustic or mechanical behaviour is not simply dictated by averaging out the properties of their constituent elements, but emerge from the precise control of geometry, arrangement, alignment, material composition, shape, size and density of their constituent elements. In terms of applications, metamaterials have phenomenal potential, in important areas, from energy to ICT, defence & security, aerospace, and healthcare. Numerous market research studies predict very significant growth over the next decade, for example, by 2030 the metamaterial device market is expected to reach a value of over $10bn (Lux Research 2019). The 'Metamaterials' topic is inherently interdisciplinary, spanning advanced materials (plasmonics, active materials, RF, high index contrast, 2D materials, phase change materials, transparent conductive oxides, soft materials), theoretical physics, quantum physics, chemistry, biology, engineering (mechanical and electrical), acoustics, computer sciences (e.g. artificial intelligence, high performance computing), and robotics. Historically, the UK has been a global leader in the field, with its roots in the work of radar engineers in the 2nd World War, and being reinvigorated by the research of some of our most eminent academics, including Professor Sir John Pendry. However today, it risks falling behind the curve. As a specific example, the Chinese government has funded the development of the world's first large-scale metamaterial fabrication facility, which has capacity to produce 100,000 m2 of metamaterial plates annually, with projects relating to aerospace, communication, satellite and military applications. The breadth of metamaterial research challenges is huge, from theory, fabrication, experiment, and requiring expertise in large-scale manufacturing and field testing for successful exploitation. We believe that the isolation of research groups and lack of platforms to exchange and develop ideas currently inhibits the UK's access to the interdisciplinary potential existing within our universities, industries, and governmental agencies. It is of the utmost importance to develop interactions and mobility between these communities, to enable knowledge transfer, innovation, and a greater understanding of the barriers and opportunities. The intervention that this Network will provide will ensure that the UK does not lag our international competitors. Via the Network's Special Interest Groups, Forums, National Symposia and other community-strengthening strategies, the enhanced collaboration will help resolve key interdisciplinary challenges and foster the required talent pipeline across academia and industry. As a result we will see an increase in research power for the metamaterials theme, and therefore reaping the impact opportunities of this area for UK economy and society. The Network's extensive promotion of the benefits of metamaterials technology (e.g., case studies, white papers etc), facilitation of access to metamaterial experts and facilities (through the online database) and closer interactions with end-users at appropriate events (e.g. industry-academia workshops) will help grow external investment in metamaterials research. Ultimately the Network will provide the stimulation of a discovery-innovation-enterprise cycle to meet desired outcomes for prosperity and consequentially, society, defence, and security.