Checking your facts
UK Electricity grid losses are more like 7%: http://en.wikipedia.org/wiki/National_Grid_(UK)#Losses
DEFRA lists petrol as 0.28455kg CO2e/kWh, whereas electricity is 0.04609kg CO2e/kWh with % transmission and distribution losses as 7.4% (2008 figures); see http://www.defra.gov.uk/environment/business/reporting/conversion-factors.htm
A Li-ion Battery charge/discharge cycle is 80-90% efficient, and EV electric motors >90%. All of which works out that electric cars are around three times more efficient than petrol cars, even when charged using a conventional fossil-fuel heavy power grid.
Whilst mining and refining the metals in batteries is not environmentally benign, the metals can be recycled at the end of the batteries life, using less energy than mining new material. Extracting and refining oil creates a large number of toxic by-products, and presents a considerable risk to the environment, as BP demonstrated this year. http://en.wikipedia.org/wiki/Oil_refinery#Safety_and_environmental_concerns
Finally, read this article on the efficiency Hydrogen Economy, it's not as rosy as you assume, basically, electric cars win: http://dx.doi.org/10.1016/j.techsoc.2003.09.024
In summary, your 'BAN battery powered cars' call may be a little wide of the mark...