I'll start by saying in no way do I know any other details than those already stated here and in no way assume due to this claim whether there is any accuracy in it.
The point of interest (to me at least) is that in the article the GMP say they received the call then contacted BA. One would assume therefore that if BA then cancel the flight following this warning there is perhaps no legal case to answer as a result. Of course this does not resolve the incident but is therefore the legal side ended?
regards