As almost all regular readers will know the quoted mpg figures bear little or no resemblance to real life. How do manufacturers arrive at figures for electric car mileage? Is it by a set formula and regulation as with petrol / diesels or are they free to do their own thing?

Surely figures must be wildly affected by conditions, how can a cold, wet, winter day requiring lights, wipers and heater compare with a warm dry summer day?

As an added point if a lot of electric vehicles were to get stuck on a snowed in motorway how would they get home if their batteries go flat? The AA or RAC cannot bring a can of fuel along can they?