A diverse student population is a relatively recent feature of the higher education system in the United Kingdom. Consequently, it may be thought that more "traditional" types of assessment based around essay writing skills for science undergraduates may be of decreasing value and relevance to contemporary students. This article describes a study in which the process of feedback on, and associated redrafting of, an essay was closely supervised to improve essay writing skills and subsequent exam performance. The results of this study show that students can significantly improve their learning and academic performance, as assessed by final examination mark, by a process that more closely mimics a "real-world" situation of review and redrafting. Additionally, the data show that students benefit from feedback only when this is used appropriately by the student. The article also discusses the continuing importance and relevance of essay writing skills so that writing, and acting upon feedback to do with that writing, remains an integral part of the process of learning. (Contains 2 tables and 1 figure.)