Environmentalists are celebrating after winning a court case over plans to expand a ski resort in one of Bulgaria’s national parks.

The scheme, approved by Bulgaria’s government late last year, was ruled illegal by the country’s special administrative court on Monday.

Critics claim it would see the construction of 333 kilometres of ski runs through Pirin National Park, a UNESCO World Heritage site.

Bulgaria's environment ministry argues the proposal would see construction in only 2% of the park’s territory and is aimed at boosting winter tourism.

“This is great news for Pirin and its supporters who have been taking to the streets throughout the bitter cold winter months after the government decision in more than 20 cities in Bulgaria and dozens more around the world,” said Katerina Rakovska, a conservation expert for the World Wide Fund for Nature (WWF) in Bulgaria.

“This court decision confirms what WWF has been saying all along: that the plans to open up Pirin to ski infrastructure construction and increased logging are illegal.

“We are delighted with the ruling as it means the government must now ensure that all threats to Pirin, one of Europe’s most special places, are assessed and avoided.”

It comes amid another controversial construction project in one of Bulgaria’s most-cherished nature sites.

It backed construction of a new road from Sofia to Greece on the understanding it would tunnel under Kresna Gorge.

But campaigners say after millions of EU taxpayers’ money was spent on less controversial sections of the road, Sofia scrapped the idea of a tunnel and approved plans to build the road straight through the nature site.

Euronews asked Bulgaria's environment ministry to comment on Monday's court ruling but it has not yet responded.