Background: We sought to evaluate the effectiveness of a national antimicrobial stewardship intervention, the Quality Premium (QP), on broad-spectrum antibiotic prescribing and Escherichia coli bacteraemia resistance to broad-spectrum antibiotics in England. Methods: We used longitudinal data on patients registered with a general practitioner in the English National Health Service and patients with E. coli bacteraemia notified to the national mandatory surveillance programme between January 2013-December 2018.We conducted an ecological analysis using interrupted time series (ITS) analyses and generalised estimating equations (GEE) to estimate the change in broad-spectrum antibiotics prescribing over time and change in the proportion of E. coli bacteraemia cases where the causative bacteria were resistant to each antibiotic individually or to at least one of the five antibiotics, after implementation of the QP. Findings: Following the implementation of the QP in April 2015, we observed an immediate downward step-change in broad-spectrum antibiotic prescribing incidence rate of 0.867per 1000 patients (95% CI: 0.837 to 0.898, p