The British company behind controversial plans to drill for oil and gas in the Sussex countryside has been accused of operating in a "Machiavellian" manner after publicly playing down the prospect of fracking being used while privately promoting opportunities for "dedicated fracking" to its potential investors.

Celtique Energie, which has four licences to test for reserves in southern England, has submitted a planning proposal to West Sussex County Council to construct a temporary exploration well on land near the villages of Wisborough Green and Kirdford, and is due to submit an application for a second well near Fernhurst in the South Downs National Park.

The company's public consultation has stressed that no hydraulic fracturing - which involves injecting at high pressure a mixture of water, sand and chemicals into the earth to release gas reserves - will take place as part of these applications. Celtique have also said any use of fracking at Fernhurst is "hypothetical".

But documents obtained by The Ecologist reveal how the company has been offering potential investors the "potential for cost optimisation via an extensive drilling campaign assisted by dedicated drilling and fracking" as far back as 2011.

The 'Weald Basin Farm-In Opportunity' (farm-in is industry jargon for sub-contracting) document, marked as "private and confidential", outlines an "attractive opportunity for interested parties to acquire a position in large scale exploration acreage with a major shale gas and shale oil potential as well as multiple unconventional gas prospects in one of the world’s largest gas markets which offers attractive gas prices."

Extracting such unconventional gas reserves will require the company to use fracking, or other "unconventional" techniques, something local opponents say they feared all along. They have described fracking as the obvious endgame.

A spokesperson for the opposition group Keep Kirdford and Wisborough Green (KKWG) said:

"This document clearly shows that Celtique have no intention of standard drilling and that the oil and gas is only extractable by fracking. Why isn't the planning application honest enough to include this? The consultation with the villages stressed they were not targeting shale gas."

KKWG argue that Celtique's potential plans to use fracking must be borne in mind when planning authorities consider the application:

"The planning system is failing not only local residents but the drilling companies, to whom they apply for exploration and then extraction. If the system was honest on all accounts it should ask for the long term plans to be assessed."

And in a formal submission to the planning application for drilling at Wisborough Green, David K. Smythe, Emeritus Professor of Geophysics at the University of Glasgow, recently said:

"There is no other possible outcome [than fracking], apart from withdrawal from the site after this stage ... the application must be considered in the context of the intention to frack."

Geoff Davies, Celtique CEO, denied the claims. He told The Ecologist: "From the outset Celtique Energie has been completely open and transparent in our engagement with the Sussex communities in which we are proposing to operate.

"At the numerous public consultation events, one-to-one community surgeries and presentations we have held with local people and elected representatives in Fernhurst, Kirdford and Wisborough Green, we have consistently stated that as part of our exploration programme we would take log and core data on shale rock formations encountered in both proposed wells.

"Until such time as Celtique has acquired this initial data, it is impossible to confirm the extent of the commercial potential present and how it could benefit the nation. For example, the resources could be shallow or deep; oil or gas or both; small or large; conventional not requiring hydraulic fracturing; or unconventional that does require future hydraulic fracturing."

"As a result, Celtique is not in a position to provide details on potential future appraisal wells or production scenarios until such time as it has acquired this initial data.

"However, all future activity beyond the initial phase of exploration proposed by Celtique would be subject to a separate planning application, further extensive consultation by Celtique with the community and the necessary additional permits from the Department of Energy and Climate Change and the Environment Agency."

But environmentalists say the fracking industry has become more canny in its PR following the high profile protests that accompanied exploratory drilling by Cuadrilla Resources in the Sussex village of Balcombe.

Brenda Pollack of Friends of the Earth commented:

"Companies have become more wary of using the 'F' word because most people know what fracking means for the local environment and climate change.

"These problems are even more concerning when Celtique’s sites in Sussex are in or very near to the South Downs National Park – an area of such sensitivity it’s been given the highest level of landscape protection. Shale gas is another dirty fossil fuel that we can’t afford to burn. We need to see greater investment in clean renewable energy not more dirty fossil fuels."

Local residents have also criticised the document's characterisation of the Sussex area, described as having "a low population density with primarily farm land with intervening forest coverage enabling better harmony between well site locations and the environment."

KKWG retorts: "This document shows the true picture of Celtique's conceited opinion of people that live in the UK countryside. Celtique have never drilled a well and this document highlights the Machiavellian ways they operate. It begs the question if Sussex - and indeed the whole of the UK - is up for sale to foreign investors and makes us wonder who does our land belong to?"

Celtique's Davies said in a statement: "As the UK oil and gas industry has already proven, onshore exploration and production of hydrocarbons and the conservation of the UK’s much cherished landscape are not mutually exclusive."

"There is already a number of producing well sites and other mineral workings in National Parks across the nation, including oilfields at Singleton, Horndean and Markwells Wood: the latter of which went into production after the South Downs National Park was formed.

"These facilities help support local infrastructure and services through the tax revenue they generate, and at the same time have minimal impact on local communities through natural and artificial screening owing to rolling countryside and wooded areas."

In October, The Ecologist revealed how Celtique had lined up Halliburton, the American oil services giant that featured prominently in the Deepwater Horizon disaster, as a potential contractor. Internal documents revealed that the company had held meetings with Halliburton about farm-in deals for three of its areas of operation in Sussex.

The documents stated that Halliburton, which was in September fined $200,000 (£125,000) by the American authorities for destroying evidence related to the aftermath of the Deepwater Horizon spill, had been shown data relating to the exploration wells and "appear keen".

The company's plans to carry out exploratory drilling have proved increasingly controversial: Nick Herbert, the Tory MP for Arundel and South Downs, recently wrote to West Sussex County Council to highlight the "hundreds of letters, emails and telephone calls" he had received from anxious local people about the proposed drilling near Wisborough Green.

Among the concerns Herbert highlighted was the effect of the drilling on livestock. The MP cited a dairy farmer worried about the impact from the noise and lighting on his cows and any possible reduction in milk production that this may cause. Sussex is an important agricultural area. Dairy cattle are housed near the proposed Wisborough Green site and there are livestock adjacent to the site earmarked at Fernhurst.

In September, a leading US researcher told The Ecologist that fracking for gas and oil in the British countryside poses such a significant risk to livestock that a moratorium should be imposed on the industry until its impact on food safety can be assessed.

Professor Robert Oswald, co-author of the first study into links between hydraulic fracturing and sickness in farm animals, said his findings of deaths and deformities in American livestock were so alarming that Britain should halt growth of the practice while further research is conducted.

One Sussex farmer, responding to the initial Celtique planning application submitted to the South Downs National Park Authority, said:

"My family has been farming adjoining land since the early 1960's, and has experienced difficult times over the years which has included the BSE crisis, foot and mouth and economic hardship. However we have endeavoured to adapt and change in order to continue to live a life which is reliant on and respects the countryside.

"The impact of drilling and possible future fracking will change our lives forever, as it is known that this process both pollutes the land and causes serious health issues. There are two babies and three children under 10 living nearby - will you be responsible for their future health and well being if this goes ahead?"

Another farmer told The Ecologist:

"We don't know enough about fracking, nobody does. Not us or them. If they get it right, fine, but if it goes wrong and we end up with pollution and sick animals, it'll be us, not them that will suffer."

Advocates of fracking say it is safe for people and the environment, and reduces reliance on imported gas.

But critics argue fracking involves an unacceptable level of water usage, contaminates water supplies and spills potentially toxic waste into the environment. They also say the process uses an unsavoury mix of chemicals - including known carcinogens - and is a cause of air pollution, traffic congestion, noise, and a host of other problems.

The government has thrown its support behind the controversial technology, with Britain's so-called 'dash for gas' expected to accelerate in 2014.

Andrew Wasley is investigations editor of the Ecologist and the Ecologist Film Unit