I don't know the precise UK numbers, but a complete switch to electric cars would mean 20% more electricity consumed from the grid. This is not a huge increase,

I don't know the precise UK numbers, but a complete switch to electric cars would mean 20% more electricity consumed from the grid. This is not a huge increase, in most places the grid should be completely fine to sustain the extra load. Especially, as car charging is wonderful for grid balancing, you mostly wouldn't do it in the moments of highest grid demand. Yes, residential electricity consumption would about double, but that isn't a huge challenge for the grids either. The biggest change would be adding some more transformers which provide the 230V to households. But as the changeover to electric cars will take like 20 years, this is absolutely doable - and in Germany the electric providers started already the planning.