This paper presents an evaluation of the use of environmental valuation – techniques to assign monetary values to environmental impacts of policies and projects, especially nonmarket impacts – in U.K. policy. In doing so, we seek to contribute to the debate, more generally, of the use and influence of benefit-cost analysis (BCA) in national policy processes such as Impact Assessment. Specifically, our contribution in this paper is two-fold. First, we identify a number of trends that have characterized U.K. policy use of environmental valuation over the past two or so decades. While this has notably involved development of “sharable values” allowing more widespread uptake, it also seems that different branches of government have developed different traditions of use adding nuance to what, on the face of it, is otherwise a shared endeavor. Second, we evaluate the extent to which the use of environmental valuation can be said to have influenced policy decisions and the degree to which this is embedded by evolving policy processes. As such, we discuss two areas of environmental policy – water quality improvements and natural capital – which have entailed either substantial use of environmental valuation either in determining specific policy and investment project options or where this has helped shape the broader policy agenda. Our evaluation is not exhaustive; nor do our findings suggest that environmental valuation and BCA are necessarily the dominant driver of decisions, as we discuss. However, in recognizing this, we argue it is also important to consider a number of established or evolving cultural and legal institutional processes which broadly appear to support our assessment of such cases.