This article responds to two key concerns in science education: firstly, that policies designed to assess practical work have distorted its use as an effective pedagogical tool. Secondly, it addresses concerns about the lack of research on the assessment of practical work. The article analyses the policy trajectory for the assessment of science practical work, through the GCSE, in the English National Curriculum from 1988 to the present day. Drawing on published research and policy documents, using Bowe, Ball and Gould's policy cycle approach to policy analysis, we first identify three distinct eras which represent different ways of assessing practical work from 1988 to the present day. Second, we demonstrate that the interaction between high‐stakes assessment narrows the ways practical work is conducted in schools. The interaction between curriculum policy and assessment policy and its influences on pedagogy for practical work has been influenced by the high‐stakes nature of the tests. This is not a unique case to England nor to science education. Finally, we question whether we can design assessments, ‘tests worth teaching to’, that can withstand the implications of high‐stakes testing.