The answer to the above question is when the BBC says so!
"A letter to the Telegraph today by Eric Abraham former producer of BBC Panorama notes that:-
The BBC Arabic Service in line with the BBC World Service policy is that the Charlie Hebdo killers are not 'terrorists' but :-
"Two men who killed 12 people in an attack on the office of a satirical magazine."
What about using 'killers' or 'murderers' or as they inspire terror why not TERRORISTS?"
Eric Abraham finishes by saying " I am shocked at the climate in this country in which the most obvious term is deemed unacceptable through fear or misguided political correctness. Shame on you BBC."