The current PHEV's are a joke, and in this country (and others I assume) they are being used soley as a tax cheat. I remember about 10 years ago seeing a story ( then the actual car! ) about a VW Golf 3 cylinder diesel mated to a electric motor, a very early hybrid. But it died a death because the US market were very against diesels at that time, and the funding was pulled. My dad had the little 3 cyl tdi in a Polo at that time, and it was an awesome little thing that was fantastically economical, actually thinking about it that was back in 2003-4 I think. The know how has been around a long time, decades perhaps, but the willingness , for whatever reason, not.