As for major companies moving out of London, I feel most would not,
for fear
of losing their 'competitive edge'.

Possibly years ago , but these days given most communications are
electronic
it shouldn't really matter. If a large company relocated to a perhaps
slightly
depressed region it could do wonders for the local economy plus it
would be
cheap to live in for the employees (at least initially) and would take
some pressure
off london. Unfortunately london like most big cities suffers from the
black hole
effect , the more people come in , the stronger the attractions to
others becomes
so they more in too and so forth until you end up with a nightmare like
Mexico
City or Tokyo which have the population of a medium sized country each.

B2003