It's not so much the annual VED but the fuel tax. If everyone switched to electric the government tax take would be hugely reduced. They won't be happy with that so will need to find a way to tac electric vehicles to replace the lost revenue. To tax the bulk electric supply would be political suicide as you would be taxed on your domestic electricity whether you had a car or not and whether you used it 5 miles a year or 50k miles. One solution is toll roads, but that would mean people who only ever drive in town would pay nothing (though so called congestion charges avoid that anomaly). It would lead to increased usage of non-toll roads where parallel routes exist where people avoid the toll roads to avoid the tax. HGVs are taxed currently by mileage so extending that would be one solution. In NZ in the 90s they taxed diesel cars (for private use) by the mile (which actually showed up another issue in that the more mpg your car did the more tax per litre you paid). The technology exists to make this quite easy to implement. GPS coupled to roadside transducers to track vehicles would be one solution but the brings up privacy issues where every person could be tracked anywhere in the country (at least with mobiles you can turn them off or go to flight mode if you don't want to be 'tracked'). Another option would be metering at the vehicle where the car tracks how much electricity it's used and the individual is billed on that.