If US Pilot flying UK reg plane and....
 

for UK company but never touching down in the UK - does the CAA still have anything to do with these US pilots???? Do they have to be validated by the CAA etc.

Quite simple: to operate a British-registered aircraft, you need a British licence and will be regulated by the UK CAA in all respects.

It don't make no never-mind where you are operating it.

Being picky, but a JAR license or foriegn license with a validation will do:ok:

A good example is an arrangement that Miami Air, a US charter carrier, and Excel have entered into. Miami Air and Excel share a 737-800... Summers in England, and Winters in the US. A select few Miami Air Pilots come to England and obtain a validation. They fly the Excel aircraft when in the US during the winter months, and England during the summer months. A select few from Excel get a US ATP so they can act a crewmembers on the US registered aircraft.

Yup. Don't First Choice and Canada 3000 do a similar thing?

What if (hypothetically of course) a UK CAA not JAR, cpl holder is in command of a US "N" reg biz jet outside of the uk??
legallities anyone?

To fly a US reg bizjet you need either an FAA licence or a licence from the state whose airspace you are in. If you are not in UK airspace then a CAA licence is so much scrap paper. Even a JAR licence is a bit of a grey area. The FAA are happy with it, but I'm not sure I'd like to try and explain to a French inspector that I was flying a US registered aircraft on a UK issued licence in France...:ugh: