LAWYERS for the ABC have sent a warning to Woolworths, after the supermarket giant used the wall of the broadcaster’s Collinswood headquarters for a guerilla advertising campaign.

An Advertiser reader spotted a Woolworths advertisement being beamed on the side of the building on Sunday night and took a photo.

He said two men were projecting the ad from the back of a van.

ABC radio host Michael Smyth has tweeted: “Woolworths has been sent a letter from the ABC’s lawyers after using the wall of our Adelaide HQ in a guerilla marketing campaign.”

A Woolworths spokesman said the ABC, which owned the building, would not have been aware of the campaign.

“Woolworths has engaged in a short-term guerilla advertising campaign to highlight our Show Stopper Specials,” he said.

“Owners and tenants of buildings on which the projections were displayed would not have been aware that they were going to be used.”

City of Prospect director of community, planning and communications Nathan Cunningham said the council had not been notified about the ad.

Woolworths has been sent a letter from the ABC's lawyers after using the wall of our #Adelaide HQ in a guerilla marketing campaign #891Drive — Michael Smyth (@MichaelSmyth_) September 3, 2014

“The commencement of an advertising display of this size would typically require development approval (regardless of its temporary nature), and no approval has been sought,” he said.

“The unauthorised display of a large and prominent third party advertisement on the ABC building is clearly of concern.

Hope they didn't obscure the big Matt and David billboard! @MichaelSmyth_ — Matthew Abraham (@KevCorduroy) September 3, 2014

“Council’s planning policies actively discourage the proliferation of advertising displays in an effort to help maintain the highly valued aesthetic qualities of the city.”

He said the ad could also been a distraction for motorists on North East Rd and the ABC would be contacted by council if the display was repeated in the future.

The ABC did not reply to several requests for comment.