It is a well-established norm in England that secondary school mathematics is taught in groups categorised by prior attainment. It is therefore worthwhile to report alternative practices of all-attainment teaching--but these are rare. In this article, we report aspects of all-attainment mathematics teaching in a secondary school that has maintained this practice as its norm over a considerable time, including in recent years, when a hierarchical approach to measuring mathematics learning has become the norm for accountability purposes. The teaching described here takes account of the needs and progress of different students within a common curriculum focus, and we identify key principles behind it. The article is intended to contribute to a record of all-attainment grouping practices in mathematics in England, so that these practices are not lost.