The advert may be chilling, but its scenarios are disturbingly realistic, as the parents of the Sandy Hook massacre, in which a gunman armed with a semi-automatic rifle killed 20 children and six staff members, know all too well.

Speaking to CNN, Nicole Hockley, the organisation’s managing director whose 6-year-old son Dylan was killed in the shooting, said the video was “meant to be intense.”

“This is what our kids are experiencing now in school,” she explained. “We wanted to focus on this back-to-school time because parents still think of it as this rosy time where you’re getting your staplers, shoes, folders and binders…Whereas, it’s back to a time of violence for a lot of kids.”

In an area of rising mass shootings and unparalleled gun violence, the need for gun reform is more urgent than ever. No-one should be forced to endure a life-or-death situation when they venture out in public, not least schoolchildren when they go to be protected in the care of the educational system.

Yet, according to the Gun Violence Archive, there have been 302 mass shootings in the US this year so far, while Donald Trump has only responded to recent fatal shootings with the promise that “serious discussions” about background checks are under way.

Gun violence: This harrowing back-to-school advert shows the urgent need for gun reform