A mobile phone mast could be erected near a Northumberland school following a blunder by the county council.
The authority refused consent for the mast, just yards from Darras Hall First School, but failed to notify Telefonica O2 within the required 56 days.
As a result the 41ft (12.5m) mast could now be installed by default.
The council said there was an oversight in the interpretation of regulations, and that discussions were ongoing to try to agree an alternative site.
The proposed site is close to the school's pedestrian entrance on Broadway.
Eighteen letters of objection were received, but as the mast is less than 49ft (15m) tall it does not require planning permission, according to the local authority.
However, council planners can refuse consent based upon location and design, and did so at a meeting in May, when they called the mast a "highly conspicuous and alien structure".
A spokesman for Northumberland County Council said: "Unfortunately the 56 days ran out just before the meeting on 14 May, a point that was overlooked when the application was considered initially at committee.
"We have apologised publicly for this at the West Area Committee on 11 June and officers are actively working to try to resolve the situation, including meeting with the phone mast company to see if a more suitable alternative site can be agreed."
The phone company has agreed to meet the council, he added.
A spokesman for Telefonica O2 said the company was in the process of building a third generation network required to take the UK into the future.
He said the firm understood local people's concerns and was willing to meet with them to hear alternative suggestions.
Eight years ago, another telecommunications company tried to erect a mast on Broadway but the plans were dropped following protests from parents.