Peter wrote:

Actually that is definitely not the case; for example you can fly an
N-reg aircraft here in the UK (UK only) on a UK issued PPL. You can

as far as the FAA is concerned, the relevent regulations is 14 CFR 61.3:

"...(a) Pilot certificate. A person may not act as pilot in command or
in any other capacity as a required pilot flight crewmember of a civil
aircraft of U.S. registry, unless that person—

(1) Has a valid pilot certificate or special purpose pilot authorization
issued under this part in that person's physical possession or readily
accessible in the aircraft when exercising the privileges of that pilot
certificate or authorization. However, when the aircraft is operated
within a foreign country, a current pilot license issued by the country
in which the aircraft is operated may be used; and..."

also fly a G-reg aircraft on an FAA PPL and, because the UK
automatically validates ICAO PPLs when used on G-reg aircraft, you can
fly that G-reg worldwide.

are you sure about this? i.e., it is also my understanding that
one can fly a G- registered aircraft in the UK (and Isle of Man and
Channel Islands ;-) with an ICAO license other than a British/JAR
one, but I thought it didn't extend to flying said G- registered
aircraft elsewhere, e.g., picking up a G- registered aircraft
in England and flying it to France say, on a US certificate (the
rule of thumb I was told about was that, out of three countries,
i.e., country of the pilot license/certificate, country of
registration of the aircraft and country where one flies, two
must be the same...); but then I might very well be wrong.

--Sylvain