Governments around the world are seeking to expedite the electrification of passenger cars. Due to the particular policy approaches taken and market conditions, different mixes of BEVs and PHEVs and of rapid and slow public charging infrastructure are starting to emerge in different countries. The question is whether this will lead to a cost-effective use of the technology. In this study we explore the relative private cost of likely future EV and charging infrastructure mixes for two case studies, the UK and California, with the aim of formulating recommendations for EV and charging infrastructure policy that is robust under uncertainty.