Originally Posted by
LondonAndy
I have only travelled with my children, not other young relatives, and even then I have sometimes got some grief from the check-in staff! The "rules" are
here and say you don't need ID for children under 16. The only additional thing I would take in your situation is a letter of authority from the parents, allowing the child to fly with you (in these days of child smuggling etc.....)
If child smuggling then you could always just get the train where there is also no need for ID or a letter of authority.