The Eurovision song contest continued to spawn unprecedented controversy days after the winner was crowned, with the 27-nation European Union criticising organisers for their “incoherence” in banning its flag from the concert hall during the final.

In an unusually sharp letter, EU Commission vice president Margaritis Schinas wrote to the Swiss-based European Broadcast Union, which organises the contest, saying its ban contributes to “discrediting a symbol that brings together all Europeans”.

In a contest already full of controversy, the European Commission said it plans “a very lively discussion” with the organisers over the ban.

Even though the 27-nation EU did not compete as such, many of its member states did, and the star-spangled blue flag is often seen as a unifier for all involved.

Mr Schinas wrote that “such actions have cast a shadow over what is meant to be a joyous occasion for peoples across Europe and the world to come together in celebration”.

The flag is on show at countless events and across the EU nations and often flies alongside the national colours from tiny city halls to massive governmental buildings.

Mr Schinas was especially bitter since the ban came only a month ahead of EU-wide parliamentary elections where the EU as an institution is an object of fierce debate and often attacked by extremist parties.

“The incoherence in the EBU’s stance has left myself and many millions of your viewers wondering for what and for whom the Eurovision Song Contest stands,” the letter said.

During the week-long contest, organisers were already roiled by the protests linked to the war in Gaza and Israel’s participation in the event on top of the controversial disqualification of the Dutch participant over an incident which was never fully explained.

Ahead of the final, a spokesperson for the European Broadcasting Union said ticket holders are only allowed to bring and display flags representing participating countries, as well as the rainbow-coloured flag which is a symbol for LGBTQ+ communities.

Swiss singer Nemo won the 68th Eurovision Song Contest on Saturday night with The Code, an operatic pop-rap ode to the singer’s journey toward embracing a non-gender identity.