Actually there is:
UK ANO August 2012 Part 6 Article 50
Quote:
50 (1) Subject to paragraph (2), a person must not act as a pilot of an EASA aircraft that is registered in the United Kingdom without holding an appropriate licence granted, converted or rendered valid under the EASA Aircrew Regulation.
Note it doesn't say "act as the Pilot in Command" it says "act as a Pilot"
Article 50 says "Pilot", but the CAA explanatory letter states "this term is defined in article 255(1)".
Article 255(1) does not have a definition of "Pilot" - only "Pilot in Command":
'Pilot in command' means a person who for the time being is in charge of the piloting of an aircraft without being under the direction of any other pilot in the aircraft;
Even though Article 50 paragraph 1 states "Pilot", Article 50A paragraph 1 states "a person must not act as a member of the
flight crew of
an aircraft to which this paragraph applies without holding an appropriate licence granted or rendered valid under this Order."
Para 50 talks about EASA aircraft, and 50A is non-EASA aircraft, but why does one talk about pilot and the other flight crew. Do the CAA think that only members of the flight crew can be classed as pilots - and not passengers?
Definition of Flight Crew in ANO:
'Flight crew' in relation to an aircraft means those members of the crew of the aircraft who respectively undertake to act as pilot, flight navigator, flight engineer and flight radiotelephony operator of the aircraft;
So the flight crew are involved in all those aspects of flying, and not just the controls, meaning that passengers are not classed as flight crew, and so can legally take the controls.