This paper examines infrastructural and route environment correlates of cycling injury risk in Britain. We used a case-crossover design, randomly selecting control sites from modelled cyclist routes, comparing these with sites where cyclists were injured. We then used conditional logistic regression for matched case-control groups modelling to compare characteristics of control and injury sites. Intersections were strongly associated with injury risk. High streets were associated with an elevated injury risk in final adjusted models, as was road type being primary, and a more downhill gradient. Lower speed limits and lower motor traffic connectivity were initially associated with lower injury risk, but these effects were no longer statistically significant in adjusted models. Increased road width was associated with increased injury risk in all models. Increased injury risk was associated in all models with presence of bus lane (somewhat mitigated at stops), guardrail, and fuel station or parking lot. Presence of parked cars in street view data raised injury risk in fully adjusted models, as did congestion (measured by low morning peak speeds), while higher volumes of people cycling along the street reduced it. In fully adjusted models, a statistically significant increase in risk was associated with presence of an on-road painted cycle lane. Most cycle lanes or tracks at control and injury sites were very poor, with narrow lanes, shared footways, and lack of protection at junctions. Given findings from other studies showing protective effects of cycle infrastructure, Britain must create higher quality cycle provision, avoiding narrow on-road painted lanes.