You Must have missed the part where our Manufacturing Sector is larger than France's.
Even the current government admit Manufacturing ought to be larger, but the way to grow it is to encourage enterprise. The last time the government interfered with things like car making we ended up with British Leyland.
Alright alright, here's where you have a point. However, British Leyland was an example of how NOT to nationalize an industry. You took about 20 different car companies and merged them with little rhyme or reason into one big enterprise. It was simply too big and there were far too many models of car - from the 30s to the 60s, if you owned a British car it was a stamp of quality - you knew things which were made in Britain were reliable, trustworthy, efficient vehicles. Then in the 70s, things took a major plunge and the cars we made were, for lack of a better word, crap.
The best solution to the problem of British Leyland would have been to sack a crapload of models, split it into maybe 15 companies and then sell it to the workers (which gets rid of yr. union problems to a large extent - why would the workers go on strike if they own the company?). Combine that with a regime of tariffs and you would still have a strong domestic automobile industry today. Unfortunately, the Thatcherite solution was simply to sell it off and hope for the best...