How to create business impact with Data Science. Machine learning and AI have transformed Deliveroo. Surprisingly, we find that this was achieved not by the latest theory or libraries, but from rigorous application of the principles of basic research: experimentation, incrementalism, and a bias to simplicity. In this talk, we share the case study of Deliveroo, including how these principles were applied, and how they helped transform the company, which was already at international scale before its first ML and AI efforts, from a business still heavily reliant on manual decisions to a fully automated platform with a massively improved customer offering.