Formulating adequate responses to pressing socio-ecological challenges requires effective and legitimate knowledge production and use. The academic debate has gradually shifted from a linear model of science–policy relations towards co-productive alternatives. Yet, in practice, the linear model remains lingering. This paper uses a case study of a collaboration between a Dutch research institute and a ministerial department to examine how and why this linear model is so persistent. Our analysis shows the dominance of the linear model in this collaboration, while openings for a more co-productive relationship remain largely unexplored. Our findings illustrate that an important reason for this persistence of the linear model is the lack of a convincing and attractive alternative imaginary of science–policy practices, which defines clear roles and competencies for researchers as well as policy actors involved. We argue this is symptomatic of a wider tendency among both researchers and policy actors to construct science as an obligatory passage point towards policy. However, this tendency not only enables policy actors to offload their responsibility but also fails to capitalise on the opportunities offered by these practices to explicate the politics embedded in and foregrounded by knowledge production. Such an engagement with the politics of knowledge by experts as well as policymakers can encourage more effective and legitimate knowledge production and use.