Prime Minister of Slovenia, Miro Cerar, resigned on Wednesday evening (March 14) after an infrastructure project his government backed was dealt a serious setback.

According to Slovenian daily Delo, his decision to step down was caused by a Supreme Court ruling which annulled the results of a September referendum that had approved a large railway project. The project, worth 1 billion euros, was the biggest investment project backed by Cerar’s centre-left government which came to power in late 2014.

“Today was the last straw, the railway project suffered yet another blow, and I do not wish to to take part in such events… Any credible politician would resign after this,” Cerar said on Wednesday in a government session, referring to the court decision, 24ur.com reported.

The resignation also came amid growing pressure from public sector workers who demand an increase in wages and back pay, with teachers holding a one-day strike earlier on Wednesday.

Cerar said he would continue as head of caretaker government until the next election, tentatively scheduled for May, although it remains to be seen if his resignation might trigger an early election.

Supreme Court annulls railway referendum

Slovenia’s Supreme Court decided on Wednesday to annull a September referendum in which voters approved by a slim margin a project to build a new 27-kilometre railway line from Slovenia’s main seaport of Koper to Divača in western Slovenia.

The court said that Cerar government’s decision to invest 130,000 euros in a campaign which favoured the proposal and only talked about the project’s positive effects was biased and therefore illegal. The court ordered a new referendum to be held.

In the original referendum, 53 percent of voters were in favour of the project. However, the turnout was very low, with only a quarter of eligible voters casting their ballots.

Cerar billed the project as the biggest infrastructure project Slovenia has seen in years, and said the new railway would help keep the status of Koper as the most strategically important seaport in northern Adriatic.

The project is estimated to be worth 1 billion euros. Slovenia had already received EU funding for initial works on the project, and Hungary expressed interest in investing some 200 million euros in return for transport concessions.