South Ribble Borough Council had previously thrown out the proposal for the mast - the same height as the Angel of the North or nearly five double decker buses - on a grass verge next to the A582 Penwortham Way crossroads in Whitestake.
But the applicant, CK Hutchison Networks (UK) Ltd, took the case to appeal, and has won.
In August, South Ribble Borough Council said the development proposal was too close to the new works proposed as part of the A582 Dualling Road Scheme - within the proposed construction working area and impacted on highway safety.
>>>What is the A582 Dualling Road Scheme? Click here to find out.
In his report allowing the construction, planning Inspector Conor Rafferty said: "While this is acknowledged and attracts weight, this weight is limited by the fact that the A582 Dualling Road Scheme works are the subject of an application awaiting a decision and as such there is no certainty that they will be implemented.
"In any event, on the basis of the City Deal Delivery Team plans submitted by the Council, views towards the immediate foreground of the footpath and pedestrian crossings would remain unchanged such the proposal would have limited impact on pedestrian intervisibility."
Concerns were also raised over the visual impacts of the proposal, and impact on privacy to neighbouring properties.
The inspector said: "Given its simple design and location among other equipment and mature trees, the proposal would not appear as an incongruous feature within the area and there would be no significant adverse visual impact".
He added: Given the distance between the site and the nearby properties, and the limited time during which any maintenance would occur on the top most part of the proposal, I do not consider that there would be significant adverse impacts on the privacy of nearby occupiers."
The applicant supplied documentation to confirm that the proposal has been designed to comply with the guidelines published by the International Commission on Non-Ionizing Radiation Protection in terms of health impacts.