This document provides guidance for local authorities in the UK on tackling socio-economic inequality. It discusses the nature of inequality in the UK and London. It then outlines the socio-economic duty for public authorities, the benefits of adopting it locally, and six key steps for implementation: conducting meaningful impact assessments, using data effectively, encouraging strong leadership, partnering with those with lived experience, community engagement, and access to justice/compliance monitoring. Examples are given of how some local authorities have adopted the duty. The document concludes with discussing next steps for authorities.