Originally Posted by
lavajava
You have already had a conversation with two lawyers in this thread.
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.