The company behind long-term oil extraction at Biscathorpe in the Lincolnshire Wolds was accused today of inconsistencies in its plans.

Egdon Resources was challenging a refusal of planning permission for oil production and drilling a new sidetrack well at the site.

An appeal hearing near Louth was told that Egdon had previously estimated Biscathorpe would produce about 2.7m barrels of oil, at a rate of 500 barrels a day. This would be removed from the site by a maximum of three tankers a day.

But today, the company described the Biscathorpe oil find as “significant” at around 6.5m barrels. It “compared favourably” with another Egdon site at Wressle in North Lincolnshire, and could exceed it, the company said.

A campaigner against the proposal, Amanda Suddaby, told the hearing:

“The maths do not add up.”

She said the figure of 2.7m barrels had been “consistent” throughout the discussions on the scheme.

“We were very surprised to hear about 6.5m barrels. Where has that come from?

“The impact of heavy goods vehicle [HGV] numbers for 6.5m barrels has never been tested through the planning system.

“They cannot remove the oil by other means. It is either three HGVs a day or 6.5m barrels but it cannot be both.”

She pointed out that Wressle was currently producing 700 barrels of oil a day and that extraction had been stimulated by low level hydraulic fracturing.

The hearing was also told that Egdon had originally applied for a 50m drilling rig and 12 weeks of testing of each of the two proposed oil reservoirs.

But today the company said the planned rig would now be almost half that height, at 26m. And it said that the testing phase would be half the previously-stated duration, at 12 weeks in total.

Natalie Dear, for the council, told the hearing that Egdon’s application document, its planning statement and the environmental statement had all said testing would be for a total of 24 weeks. Should these paragraphs be disregarded, she asked.

Egdon’s barrister, David Hardy, said:

“We have clarified in the statement of case”.

But Cllr Hugo Marfleet, Biscathorpe’s local county council, said:

“There are a lot of changes being mentioned today that should have been dealt with in the original application in the planning process.”

He accused the company of being “vague”, of “woffle” and “a bit of spin”.

Mr Hardy said this was not a “fair characterisation” of the company’s case.

Egdon had done detailed assessments of the evidence, Mr Hardy said. In the application, the company had talked about worst case scenarios, using words such as “up to”. What was being discussed today was an improvement, Mr Hardy said.

The original application was opposed by five parish councils, six public bodies, more than 200 individuals and more than 1,770 signatories of an online petition.

Egdon has said there would no adverse impact on the Lincolnshire Wolds Area of Outstanding Natural Beauty (AONB). But many of the objectors argued that it would industrialise the AONB. It also did not pass the test of “exceptional circumstances” for major development in the AONB, they said.

The application was refused, by a vote of seven to four, on the day that world leaders gathered in Glasgow for the COP 26 climate talks in November 2021.

Nick Bodian, the chair of the Biscathorpe site’s community liaison group, told the hearing today that “in many ways, nothing has changed” since then.

He said there was no evidence that Biscathorpe oil would remain in the UK market or that domestic consumers would benefit in lower prices.

Biscathorpe’s contribution to energy security over 15 years amounted to 1.5 days of UK oil demand, he said.

“This does not represent the exceptional circumstances that would justify the harm to our AONB over the next 15 years.”

He said of the development:

“It will bring noise, light and air pollution to the area, negatively impacting on people, wildlife, habitat and the tourist economy.”

He also said Egdon’s claims that the site would provide local employment were flimsy.

The company has said it would create seven-eight fulltime jobs and six parttime during production.

Paul Foster, Egdon’s planning consultant, said every barrel of oil produced in the UK reduced the need to import from abroad. He said:

“Security of supply and avoiding importing weighs very heavily in favour of domestic sources.”

He said there would be benefits from the site in taxation and business rates, indirect employment and biodiversity gains.

Egdon also dismissed local concerns about the impact of site lighting on dark skies, a key feature of the AONB. The lighting was short-term, temporary and impacts could be mitigated, the company said.

The company told the hearing that the area around the Biscathorpe already had “adhoc lighting”, including a nearby 350m tall transmitter. It said there had been only one complaint about lighting when the first well was drilled and this had been dealt with by realigning a light.

But Nigel Rockliss, a landscape consultant for the council, said of the proposal:

“It introduces an industrial process to a landscape that does not have industrial processes”.

He criticised the way Egdon had assessed the impact of the site on the local landscape. The assessment contained errors and the methodology was misleading and confusing, he said.

Nigel Weir, for the company, said there was nothing to suggest that the assessment had downgraded the landscape value of the area. The methodology allowed for flexibility, he said.

Egdon said there had been no impact on water quality during site construction and drilling. There was no risk to the nearby River Bain chalk stream, it said, and groundwater monitoring would continue.

The inspector, Paul Thompson, who chaired the hearing, will make a decision on Egdon’s appeal, on behalf of the secretary of state for levelling up.

• Mr Thompson asked reporters not to take photographs at today’s hearing. Under the Openness of Local Government Bodies Regulations (2014), filming and photography is permitted at public meetings.