Hanoverian London was a city full of people, a city built by people for people. These impressions dominate traditional studies of the metropolis to a remarkable extent. By contrast, historians have largely overlooked the ubiquitous presence of non-human animals in the city and underestimate their impact on urban life. This article challenges key assumptions about the Hanoverian metropolis by highlighting the role of its quadruped architects, and specifically its working horses. In doing so, it urges the recognition of animals as influential actors in social, urban and economic history. The article focuses on the role of the horse in brewing, a major metropolitan industry which relied heavily on equine power. Crucially, it shows that the brewery horse became more, rather than less, influential during the industrial revolution.