Well, first UK would have to get rid of fossil fuel power plants, make renewable more reliable and green, supported by nuclear, batteries themselves have to get

Well, first UK would have to get rid of fossil fuel power plants, make renewable more reliable and green, supported by nuclear, batteries themselves have to get notably more efficient, make manufacturing of the cars and batteries more green, recharging in under 5 minutes, massive recharge station network, EVs need to rapidly drop in price... yeah. It's a nice PR stunt though.