The UK must think their entire population is morons. I've never been there, I can't confirm or deny.
Someone earlier made a great point about why people buy electric in the first place. Most don't care about the emissions, they care about the cost of fuel and being forced to support the oil companies.
As for the emissions debate, there's a legitimate argument for both sides. What I find disappointing with the UK advert bans is that their reasoning is not in line with how the world classifies emissions for automobiles. The behind the scenes impact has never been included in the emissions output of the vehicle. Taken literally just one step further, there will never be a zero emission vehicle unless it doesn't include any passengers since humans emit atmospheric CO2.
The UK's Advertising Standards Agency is just being a douchbag because they can. They probably want the publicity. They're in advertising.