A shale pioneer in the United Kingdom said Thursday it was disappointed, but not surprised, by the rejection of its oil and gas exploration bid.

Celtique Energie said its application to explore shale oil and natural gas reserves in the South Downs National Park in southern England was rejected.

"We are disappointed by today's decision by the South Downs National Park Authority," Geoff Davies, Chief Executive Officer of Celtique Energie, said in a statement. "However, we are not surprised, given the authority's public stance regarding oil and gas exploration in National Parks, both in Sussex and elsewhere."

The company said it believed the untapped oil and natural gas reserves thought to be present in the area would be nationally significant.

The British government has endorsed shale reserves as part of a diverse energy mix. Shale campaigns in the country are in their infancy, however, and have been met with widespread opposition from environmental advocacy groups.

"The benefits of fracking have been hugely over-hyped," British Friends of the Earth campaigner Brenda Pollack said. "With the need to tackle climate change becoming more urgent than ever, it's time to build a sustainable energy future based on efficiency and renewable power."