Pressure of work during the pandemic led Sheffield City Council to inadvertently allow planning permission for three 5G phone masts.
This was because the applications by Cornerstone and Vodafone were not determined within the 56 days limit, leaving the applicants free to build them under the Town and Country Planning (General Permitted Development Order) 2015.
The council said two would have been permitted anyway but the third, at Rustings Road, would not.
Bob Johnson, cabinet member for transport and sustainability, said: “The council apologises for this mistake but hope people will understand we are operating in extraordinary circumstances which have led to these oversights occurring.
“We understand residents’ depth of feeling about the location of these masts and we are sorry that they were not properly determined within the time limit.”
Cllr Johnston said the council was “actively working with” the applicant for Rustings Road to try to find an alternative site.