The historian David Edgerton has an interesting take on the last part - he says that there is no longer a British national capitalism - that is that most big business in the UK is internationally owned or has an outlook that doesn't see itself as particularly British. Good examples would be motor manufacturing and chemicals (so no ICI but instead we have Ineos). There are exceptions of course but the trend is clear.

If you look at the backers of the tories now it's not big business any more (in the sense of the CBI say) but often niche financial services firms - who often loathe the EU. If you follow the money then I can't see the Tories worrying too much about traditional business in the UK.