Drawing on a secondary analysis of official statistics, this paper examines the changing scale of the inequality of achievement between White students and their Black British peers who identify their family heritage as Black Caribbean. We examine a 25‐year period from the introduction of the General Certificate of Secondary Education (GCSE), in 1988, to the 20th anniversary of the murder of Stephen Lawrence in 2013. It is the first time that the Black/White gap has been analysed over such a long period. The paper reviews the changing place of the Black/White gap in education debates and notes that, despite periods when race equality has appeared to be high on the political agenda, it has never held a consistent place at the heart of policy. Our findings shed light on how the Black/White gap is directly affected, often in negative ways, by changes in education policy. Specifically, whenever the key benchmark for achievement has been redefined, it has had the effect of restoring historic levels of race inequity; in essence, policy interventions to ‘raise the bar’ by toughening the benchmark have actively widened gaps and served to maintain Black disadvantage. Throughout the entire 25‐year period, White students were always at least one and a half times more likely to attain the dominant benchmark than their Black peers. Our findings highlight the need for a sustained and explicit focus on race inequity in education policy. To date, the negative impacts of policy changes have been much more certain and predictable than occasional attempts to reduce race inequality.