ABSTRACT: Incorporating scientific knowledge into the decision-making process is a fundamental requisite to achieve the goals of the Decade for Marine Sciences and the Sustainable Development Goals of the UN.  Indeed, scientific advice is an integral part of policy making at EU level. Any environmentally significant legislation is evaluated against the scientific evidence in order to maximize its positive impacts and returns to the society. Marine-related legislations (such as the MSFD or the CFP) are no exception so a group of dedicated marine-scientists develop new approaches and keep track of the latest developments in the field at the Joint Research Centre of the EU Commission to help with their implementation. In this talk I will present the Marine Modelling Framework (MMF), a suit of interconnected digital twins that allow simulating the impacts of different policy options on the environmental status of marine ecosystems across Europe. Different examples of the MMF application will be presented and its connections with the policy-making process will be highlighted.