The union representing correctional officers is raising the alarm after it says an inmate had a drone drop off a McDonald's meal and alcohol to what's supposed to be Canada's most secure prison earlier this week.

The union said the drone delivered McDonald's chicken nuggets and fries complete with sauce and some alcohol straight to the inmate's cell window in the special handling unit at the Sainte-Anne-des-Plaines, Que., facility at around 3 a.m. on Thursday.

"The inmate found that really funny in the morning when the guards did their rounds," said Mike Bolduc, regional president of the UCCO-SACC-CSN union, in an interview.