The availability and performance of broadband connectivity is becoming an increasingly important issue across much of the developed world as the prevalence of richer media services and growing populations have generated increasing demands on existing networks. The heterogeneous geography of broadband infrastructure and investments results in variable service provision, and as such, there exist large disparities in access and performance within different spatio-temporal locations. This paper presents analysis of 4.7 million crowdsourced Internet speed test results that were compiled between 2010 and 2013 alongside various indicators of socio-spatial structure to map disparities in English broadband speed between and within urban areas. Although average speeds have improved over time, inequity is shown to emerge between different societal groups and locations. Short-term dynamics also reveal that in areas of different density, speeds can fall dramatically during peak hours, thus influencing the availability of services. The apparent disparities in access and performance represent a major issue as Internet use becomes increasingly ubiquitous in our everyday lives, with inequalities evoking social and economic disadvantage at local and national scales. This work resonates with UK government policy that has stimulated considerable investment in improving infrastructure, and presents analysis of an expansive crowd sourced “big data” resource for the first time.