Ok, so not exactly a ‘for the public’ vehicle, but this seems, foolhardy and a bit of a waste of time and money…
Coming up with a solution to basically install cables across the whole motorway network? It’ll be easier and quicker to come up with hydrogen fuel stations and rapid battery charging stations for trucks instead - and all the major truck manufacturers, (DAF, MAN, Volvo Trucks and Daimler as well as Tesla) are already developing their own solution to this without the UK government having to come up with their own wacky ideas.
If they wanted to develop a transport network that was powered by overhead cables, how about also putting it on iron rails and making the vehicles multi-carriaged so you can get more passengers or goods on it… a bit like a train…