MJ - the debate about allegedly avoiding local regs can go on for ever, and the tax issue is bollox (we all pay loads of tax), but what I don't get is your introduction of
AOC operations into this.
AOC is completely irrelevant to the N-reg issue - unless (as I wrote earlier) you are getting hot and bothered about illegal charter, which is more likely to be done with privately owned aircraft, which is more likely to be N-reg than G-reg, but that is still irrelevant.
You can put an N-reg on a UK CAA AOC, apparently, and in that case please lay out, in detail, an operating cost comparison of a G-reg on a UK AOC and an N-reg on a UK AOC. I am waiting....
I have spoken to a couple of Commercial ATPL pilots back home in the UK who fly N reg - but as it is their profession and livelihood at stake - they also as a matter of course also hold JAA - eminently sensible. They got their JAA initially then did the FAA as an easy transition.
That is mainly true in the big multi-aircraft AOC ops which are often mixed fleets. Passenger-owned jet aircraft (privately or business owned) rarely have dual-rated pilots; no need for it. They tend to employ pilots long term. One customer of mine has an N-reg corporate aircraft whose 2 pilots have worked for them for about 20 years.