Sevenoaks District Council submitted its draft local plan for examination in April.
The document says that, under the government’s standard method for assessing housing need, it should deliver 698 homes per year over the plan period, 2015-35, or 13,960 homes in total.
However, it adds: "This is a highly constrained district with 93 per cent green belt and 60 per cent AONB and therefore, despite exploring a range of different options including green belt release, we have been unable to meet our housing need in full."
In November, the council voted to drop eight out of 12 green belt sites that had been earmarked for development in the emerging local plan.
The submitted version of the plan says the district has the capacity for 10,568 homes over the plan period including 940 on strategic sites in the green belt and 1,360 on brownfield land in the green belt.
In a post-examination letter to the council, sent last week, inspector Karen Baker said she had "significant concerns about a number of aspects of the plan, both in terms of legal compliance and soundness".
Baker said that her main concern "relates to the lack of constructive engagement with neighbouring authorities to resolve the issue of unmet housing need and the absence of strategic cross boundary planning to examine how the identified needs could be accommodated".
The inspector said: "Indeed, the council did not formally ask neighbouring authorities if they were in a position to address its unmet housing need until just before the local plan was submitted for examination.
"I am not satisfied, therefore, that the council has addressed this key strategic matter through effective joint working, but has rather deferred it to subsequent plan updates."
Baker said that she considered this to be "a significant failure in the council’s duty to co-operate. Any failure of the duty to co-operate cannot be rectified during the examination and therefore the only option is for a report recommending non-adoption to be issued or for the plan to be withdrawn from examination."
The inspector also flagged "significant concerns about the soundness of the plan in respect of a number of areas including the approach to sustainability appraisal, the chosen strategy for growth, the assessment of the green belt and housing supply and distribution."
Baker said that she would provide more detail on these in a further letter.
The inspector said that she would "not reach any final conclusions on the way forward" until the council has the opportunity to respond to that letter.
However, she advised: "I consider it is necessary for me to advise you that, at this point, I consider the most appropriate way forward for the Sevenoaks District Local Plan would be for the council to withdraw it from examination."
She added: "I have not reached these conclusions lightly and have only done so after giving you every reasonable opportunity during the examination process to address my concerns."
In a letter responding to the inspector, the council said it was "extremely disappointed".
The council said the inspector’s "initial conclusions are at odds with the independent advice that the council received in advance of submission, including our discussions with the government’s own Planning Advisory Service (PAS), the opinion of a QC and industry experts – including former senior planning inspectors".
It added: "The council believes that withdrawing the plan from examination would run contrary to the spirit of the government’s own advice on plan making. We are pleased to hear that the inspector has not reached a final conclusion on this matter and hope that a positive and pragmatic way forward can be found."
The submitted version of the plan also proposes allocating 11.6 hectares of employment land and 32,000 square metries of retail floorspace.