I know about the car industry. The Nissan plant in Sunderland, for instance, was one of the first examples of inward investment attracted by Thatcher following on from the battles with the unions. However, Britain did used to make British cars. The nationalised company was British Leyland (and hopelessly inadequate it was too). But there were others (all pretty much hopelessly inadequate in the end).
I think you'll find that;
several car companies spent some time undder state ownership
including Chrysler and rolls royce.
They were nationalised because under their various guises: rootes group(chrysler), bmc,blmc, Austin Rover and finally Rover they were a basket case but considered to be strategically important.
the battles were between unions and management . I don't thinkl such turkeys as the autin allegro, austin princess, morris marina etc etc etc were designed by trade unions. The problem with industrial relations in British manufacturing industry centred around obsolete prctices on both sides. Union membership at plces such as Nissan is compulsory, there is a closed shop-essential in keeping communications open and constent -both ways.
You said that the UK car industry concntrates on high end products. It doesn't and I gave you an answer why it wasn't, next you say you know about Nissan. I find tis a little odd.