Europe was plunged into fresh crisis on Friday as Austria’s courts ordered a re-run of the country’s presidential election.

The constitutional court ruled the election, in which a far-Right candidate was narrowly defeated, would have to be held again because of irregularities in counting postal votes.

The ruling means the far-Right may seize the presidency of a European Union member state for the first time.

Norbert Hofer, the gun-toting candidate of the far-Right Freedom Party (FPÖ) lost the election in May by just 31,000 votes.

He was defeated by Alexander van der Bellen, a soft-spoken former economics professor endorsed by the Green Party.

"Confidence in the rule of law is the foundation of a democracy," Mr van der Bellen said. "I will stand in the rerun, and I intend to win it. I urge all citizens to exercise they right to vote. This is no game. For me it is about the unity of Austria."

Mr Hofer’s supporters will hope Friday's ruling means he can seize the presidency after all.

"I am pleased the constitutional court has taken this very important decision objectively," Mr Hofer said.