Austria’s highest court on Friday annulled May’s presidential election result, citing irregularities, and called for a rerun following a legal challenge from the far-right Freedom Party (FPOe), whose candidate lost by a narrow margin.

“The challenge brought by Freedom Party leader Heinz-Christian Strache against the May 22 election… has been upheld,” said Gerhard Holzinger, head of Austria’s Constitutional Court.

The ruling presents a victory for the Freedom Party, which challenged the May 22 runoff after its candidate narrowly lost to a left-leaning independent candidate.

Norbert Hofer of the FPOe came top in a first round in April but then lost by only 30,863 votes to Alexander Van der Bellen, an independent backed by the Green Party, in a runoff.

Preliminary results on the evening had given Hofer a narrow lead but after some 700,000 postal votes were counted, Van der Bellen was declared the winner of the largely ceremonial post the next day.

The FPOe, which is topping opinion polls ahead of the next scheduled general elections in 2018 on the back of unease about immigration, launched a legal challenge on June 8 because of “massive irregularities.”

These included allegations that tens of thousands of votes were opened earlier than allowed under election rules and that some votes were counted by people not authorized to do so.

The rerun is expected to be held in September or October.

With Britain’s pending departure from the European Union overshadowing the vote, it will in some ways be a renewed reflection of Austrian, and European, EU sentiment. A Hofer win, however narrow, would boost not only the Freedom Party but kindred movements in France, the Netherlands and elsewhere lobbying for less EU power, or outright exits from the European Union for their countries.