Originally Posted by
thbe
The legal situation on an BA airplane on a international flight is defined by international law (i.p. Chicago Convention, Montreal Convention, Tokyo Convention), by national aviation laws (i.p. Air Operations/UK Regulation (EU) No. 965/2012/European Union Withdrawal Act 2018), other UK laws, CAA Guidelines and BA guidelines.
It’s impossible to answer correctly a question about a legal situation onboard of an international BA flight without referring to that.
Then perhaps you'd care to elaborate on which of these laws it is, exactly, that makes serving a 5-17 year old alcohol on a G-xxxx reg aircraft illegal?
That might help a bit more than just making mere assertions...