Chilli,
I agree, but what about that aircraft that doesn't show on radar? How, under a RAS do you provide separation from that?
the ANO refers, section IV, 17 1 (a)
"Notwithstanding that the flight is being made with air traffic control clearance it shall remain the duty of the commander of an aircraft to take all possible measures to ensure that his aircraft does not collide with nay other aircraft."