SummaryThis article seeks to advance the understanding of the relationship between industrial ecology (IE) and business model innovation for sustainability as a means and driver of new value creation and competitive advantage by expanding the understanding of industrial symbiosis (IS) and internal symbiosis. This is explored through the case study of British Sugar, which, at the time of writing, is the UK's largest sugar producer by market share. Over the past three decades, the company has systematically sought opportunities to turn waste streams and emissions from their core production processes into useful and positive inputs to new product lines. Their core business is still sugar, but the business model has evolved to offer a broad range of additional synergistic and profitable product lines, including animal feed, electricity, tomatoes, and bioethanol. The research explores the temporal dimension of dynamic business model innovation, framing it in the context of a continuous evolutionary process rather than a discrete design activity. The case will be of interest as an additional contribution to the growing literature on IS; in offering an approach for linking the themes of IE literature and sustainable business model innovation more concretely in research and practice; and, by presenting the case as an evolutionary innovation process, the article furthers the emerging literature on business model innovation for sustainability.