An investigation into Warwick District Council's handling of a controversial planning appeal has been delayed – but the councillor in charge has acknowledged and apologised for "an administrative error". 

The authority confirmed in August that it had appointed an external investigator to look into a formal complaint over the lost appeal that ended with a poultry farm in Norton Lindsey receiving planning permission. 

That case ran for more than five years but the council's sole reason for saying no the final time – on the grounds of highway safety – was not supported by highways authority Warwickshire County Council after applicant Mr A Audhali did extra work. 

It meant Warwick District Council could not fight the case with residents left infuriated, particularly as documents detailing the county's revised position had not been uploaded to the district's online planning portal until after the appeal was heard – more than six months after they had been produced. 

The inspector's report concluded that interested parties had been notified of the appeal, "so would have been able to view the additional submitted information". It is not clear whether that position assumed that the documents had been uploaded or if it was making reference to their availability elsewhere.

Warwick District Council initially said the investigation was due to be concluded by the end of September but has since confirmed that the investigator has been "asked to undertake some further work" after a review of the draft report.

The council's statement added: "The complainant is aware of the situation and agreeable to the council ensuring all aspects are covered in an appropriate timescale rather than rushing to completion."

It was confirmed the council "is awaiting an update from the investigator on revised timescale".

However, Cllr Chris King, who has political responsibility for planning in the district, admitted something had gone wrong and that measures were being put in place to prevent any repeat.

He told the Local Democracy Reporting Service: "There was a mistake there, an administrative error.

"It has been acknowledged by both sides that it wouldn't have made any difference to the decision on that application but that is not the point, an error was made, that has been fully admitted and apologies have been given.

"The complaint is live and will go through its own process. I have visited that issue and the broader issues of whether our training and support is adequate for officers because we need to make sure the procedural side of it is in place.

"Planning is a highly visible sector, we have to make sure these things are on the money."

It is not the only high-profile planning problem the district has endured. 

The council lost another planning appeal over permission for 83 homes next to Warwickshire Police's headquarters in Leek Wootton and was found to have acted unreasonably by planning inspector Steve Lee because it failed to notify the applicant Cala Homes or the body of residents that registered as an interested party about an update to its housing land supply position – how many homes are likely to be delivered in the district over the next five years. 

The council was also challenged on its land supply position and found to have overestimated it, meaning its adopted planning policies will not carry full weight when developers bring forward sites that are not allocated for building.

Cllr King was keen to avoid any finger pointing and argued that the issues were indicative of local government departments being under pressure.

"We have had longer than a decade of increasingly fewer resources and that affects not only the finances but also human resources," he said. 

"In that context, everything you do is under the microscope more than it normally is. 

"If you lose people it is not easy to recruit at the moment and we had to take all of that into account – it is not an excuse but it sets the scene.

"I am doing all I can to make sure those things are tightened up and that we are doing as well as we can to process everything we can in the right way and in the right timescales."

Asked whether Warwick District Council's planning department is adequately resourced, Cllr King replied: "It is resourced fine.

"We are doing well, we process a lot. When you look at the figures we are meeting our targets but that does not negate the fact that people are sometimes having to work extra hours to get these things done.

"We are under the same pressures that other local government departments are, that's a fact of life too and you cannot dodge that, you just have to get on and try to do the best you can.

"In those circumstances, you are vulnerable to slippage. We had a slip (on the poultry farm) and we apologise for that."

He does hold out hope of increasing resources for the planning department in the future, though, with changes to national planning policy on the horizon.

"The new (government) paper has talked about the possibility of planning authorities being able to charge fully for their services," added Cllr King. 

"That is a very exciting prospect for all authorities because we currently have to carry costs. If that goes through it will make a difference, we can have the prospect of being able to give them additional resources."