The leaflet, which was circulated among 1,000 homes in the Sheffield area, advertised air weapons including sniper rifles and handguns as well as a long reach machete under special offer.
The Advertising Standards Authority (ASA) ruled it was “likely to cause serious and widespread offence” after a complaint was filed against firearms dealer Atlas Arms, citing that the ad was “offensive and irresponsible”.
The Sheffield-based retailer, responsible for the leaflet which was dropped through people’s letterboxes, featured offers such as “Black Ops Sniper Rifle...£250 RRP £269.95 includes free pellets”.
Other offers included a £15 long reach machete and “free local delivery straight to your door on orders over £100”, alongside images of the goods on pages entitled “special offer”.
But despite an over-18 age warning and a requirement for photo ID stated, the ASA ruled that the brochure could potentially be seen by children as it was unaddressed.
The ASA said: “We acknowledged the ad stated prominently that customers must be at over 18 years to buy the items, and photo ID was required.
“However, the ad was distributed via a door drop to people’s homes on the basis of their postcode, and was not contained in an addressed envelope.
“Because the brochure for weapons could therefore be viewed by any person at those addresses, including children, we considered it was unsuitable for an untargeted medium and irresponsible in that respect.”
Concerns about rising levels of knife crime nationally and locally also influenced the ASA’s decision.
The ruling read: “The ad featuring guns and knives had been delivered directly into people’s homes, during a climate of widely reported concerns about rising levels of violent crime, in particular knife crime, both nationally and in Sheffield.
“Therefore in that context, we considered those factors also contributed to the ad being likely to cause offence to consumers.”
Atlas Arms said their advert “did not depict any scenario for which the items would be used” except for a picture of a target, intended for use alongside one of the air pistols advertised.
They added that no firearms were featured in the ad and that the brochures were distributed by a third-party company.
The authority also ruled that “promotional messaging” and large imagery of featured items could cause offence to consumers.
The ruling read: “We also considered that the decorative knives featured in the ad were likely to be different to the functional knives and blades that consumers typically saw in high street shops.”
Atlas Arms said “many hardware shops on the high street” sold knives.
The watchdog ruled that the advert should not reappear in its current form and in future, such ads should not be given out “untargeted”.