Policy making is called to play a decisive role in the commercialisation of tidal stream energy projects. For they are site-specific, spatial targeting of policies is needed, so that tidal stream regulations (financial supporting mechanisms, consenting procedures, etc.) could be concentrated to sites where they can achieve the greatest benefits. With this in view, the aim of this paper is: (i) to develop a new method to delimit the most suitable (target) areas for tidal stream energy policy intervention within a coastal area of interest, and (ii) to apply it to the Bristol Channel and Severn Estuary (UK). The method includes spatial numerical analysis by means of a Matlab-based code coupled with a Navier-Stokes solver. The programme works in steps, in which different constraints are imposed with a view to carry out a zoning process. As a result of this zoning process, four hotspots are selected, for which a set of policy interventions is proposed. This includes the specific levels of subsidisation for closing the grid parity gap of potential projects in each area. The method can be viewed as a supporting decision mechanism for spatially targeted policy-making and management of tidal stream energy across the Bristol Channel and Severn Estuary.