A shale company has decided it will not appeal against decisions to refuse planning permission to explore for oil and gas at two sites.

Celtique Energie had applied to drill a temporary well to test for oil and gas in the South Downs National Park, near the village of Fernhurst, West Sussex, but the application was turned down in September last year.

The company announced today that it would not be opposing the refusal to grant planning permission, just one day before the deadline by which an appeal could be lodged, claiming there was too much uncertainty in new planning guidance relating to oil and gas developments to justify an investment in a national park.

The proposed exploration well would have tested for the presence of conventional oil or gas in the Kimmeridge Limestone and Great Oolite formations, taking log and core data in the Kimmeridge and Liassic shales, Celtique said.

A spokesman said: "However, recent changes in the Infrastructure Act 2015 restricting unconventional oil and gas development in national parks mean that one of the exploration aims, namely the evaluation of the shale properties, is no longer feasible.

"This is in conjunction with the Department of Communities and Local Government (DCLG) reinforcing new planning guidance regarding oil and gas developments in national parks in England, stipulating that applications should be refused in these areas other than in exceptional circumstances and where it is in the public interest.

"At present there is too much uncertainty over how this test will be applied in practice to justify investment in national parks."

Celtique also said it was withdrawing its appeal against West Sussex County Council's planning committee who refused its application for oil and gas exploration near Wisborough Green, a conservation area just outside the South Downs National Park, in July.

The county council said it had turned the application down because Celtique did not demonstrate the site represented the best option compared with other sites, it had unsafe highways access and would have had an adverse impact on the area.

The company lodged an appeal with the Planning Inspectorate, claiming the council's reasons for rejecting the application were "fundamentally unsound".

But it withdrew the appeal today claiming delays which had pushed the inquiry date back from February to September, and the unavailability of a suitably qualified planning inspector, would impact on future exploration and potential appraisal operations which needed to be completed in order to deliver a development application within the licensed time period.

The spokesman said: "By the time the inspector's decision is received and the period for any third party legal challenge to that decision has expired, there will be insufficient time to drill a well at this location prior to the end of the licence term in June 2016."

The decision not to go ahead with the appeals was welcomed by Friends of the Earth who called it "a tremendous victory for common sense".

Brenda Pollack, Friends of the Earth South East campaigner, said: "I am absolutely delighted. This is a tremendous victory for common sense and yet another blow to the coalition's short-sighted fracking plans.

"The withdrawal of their appeal at Wisborough Green was completely unexpected. It is wonderful news for local people in those villages and beyond who do not want dirty drilling affecting their communities.

"The South Downs National Park Authority and West Sussex Council were right to reject these schemes and we hope that other companies take note."