RadioNet is a consortium of 28 institutions in Europe, Republic of Korea and South Africa, integrating at European level world-class infrastructures for research in radio astronomy. These include radio telescopes, telescope arrays, data archives and the globally operating European Network for Very Long Baseline Interferometry (EVN). RadioNet is de facto widely regarded to represent the interests of radio astronomy in Europe.A comprehensive, innovative and ambitious suite of actions is proposed that fosters a sustainable research environment. Building on national investments and commitments to operate these facilities, this specific EC program leverages the capabilities on a European scale.The proposed actions include:- Merit-based trans-national access to the RadioNet facilities for European and for the first time also for third country users; and integrated and professional user support that fosters continued widening of the community of users.- Innovative R&D, substantially enhancing the RadioNet facilities and taking leaps forward towards harmonization, efficiency and quality of exploitation at lower overall cost; development and delivery of prototypes of specialized hardware, ready for production in SME industries.- Comprehensive networking measures for training, scientific exchange, industry cooperation, dissemination of scientific and technical results; and policy development to ensure long-term sustainability of excellence for European radio astronomy.RadioNet is relevant now, it enables cutting-edge science, top-level R&D and excellent training for its European facilities; with the Atacama Large Millimetre Array (ALMA) and the ESFRI-listed Square Kilometre Array (SKA) defined as global radio telescopes, RadioNet assures that European radio astronomy maintains its leading role into the era of these next-generation facilities by involving scientists and engineers in the scientific use and innovation of the outstanding European facilities.