The Sydney SP bookmaking scandal of 1936 is all but forgotten now, but its historical significance is enormous. It was the first public exposure of systemic police corruption in 20th century Australia. The scandal began with a routine police raid on a smallgoods shop in Dulwich Hill and a minor charge of illegal betting. It lead to a royal commission which exposed widespread police misconduct and extensive corruption, lead to the dismissal of 13 police, and shook public confidence in the New South Wales Police Force. The SP scandal presented a valuable opportunity for reform, but this did not occur – a failure which is revealing in itself. This paper looks at the urban and social geography of the illegal betting industry in Sydney in the 1930s and its associated police corruption. It explores how illegal gambling caused different social and geographic worlds to intersect, leading to unlikely alliances which were able to mobilise scandal and force a public inquiry.