The JRP aims to deliver metrologically sound measurement of fundamental radiological quantities such as ambient dose equivalent rate, radioactivity concentrations in air and ground contamination levels in real-time. This requires novel multidisciplinary approaches to be taken by a European collaboration of metrology and research institutes, including the JRC at Ispra which is responsible for the EURDEP database, accompanied by stakeholders and manufacturers of radiological monitoring detector systems. This JRP will provide the unique possibility to comprehensively address the harmonisation of the radiological early warning networks in Europe – the largest and most comprehensive environmental radiation monitoring system worldwide.