Long waiting times for inpatient treatment in the UK National Health Service have long been a source of great popular and political concern, and therefore a target for policy initiatives. One such is the London Patient Choice Project, under which patients at risk of breaching inpatient waiting time targets were offered the choice of an alternative hospital with a guaranteed shorter wait. This paper uses a difference in difference econometric methodology to infer the impact of the choice project on ophthalmology waiting times. In line with our theoretical predictions, it finds that the project led to lower average waiting times in the London region and a convergence in waiting times amongst London hospitals.