It'd truly be one of the biggest infrastructure projects the UK has ever seen and likely run into the £100's of bns. The disruption would be like nothing ever seen before (you can't just upgrade substations or dig up basically every residential street in the country without disruption).
I think many like to comment on this from the position of being one of the few who owns an electric car and has the luxury of finding places to charge. That does not scale without truly colossal infrastructure changes.