Brussels authorities ordered the shutdown of a two-day gathering of radical right-wing leaders and pundits in Brussels on April 16, triggering a political firestorm as the Belgian PM and other leaders condemned the ban as an assault on free speech.

Organisers of the National Conservatism Conference (NatCon) announced on Wednesday morning that the conference would go ahead "despite frantic and continuing efforts" by Brussels officials to cancel it at the last minute.

The conference demonstrates the spread and rise of the radical right in Europe. The radical right European Conservatives and Democracts (ECR) and the far-right Identity and Democracy (ID) groupings are expected to do well in the European Parliamentary elections in June. The ECR could even leapfrog the parliament's liberal grouping to become the third largest.

Hungarian Prime Minister Viktor Orban and former Polish PM Mateusz Morawiecki are set to address the conference on Wednesday if it goes ahead. Other speakers include the eurosceptic populist Nigel Farage and Britain's former interior minister Suella Braverman and far-right French politician, presidential candidate Eric Zemmour.

Despite the confusion, speakers on stage pressed on with speeches on Tuesday touching on themes such as transgender rights, "wokeism",  challenging the EU "superstate" and multiculturalism.

NatCon organisers had been scrambling for a place to host the fundraiser since Friday evening when the Brussels reception room they initially booked abruptly withdrew. The second venue was supposed to be Hotel Sofitel Brussels Europe, but management pulled out at the last minute, saying they had been misinformed about the nature of the event.

The Mayor of Etterbeek Vincent de Wolf of the liberal Reformist Movement boasted to The Brussels Times that he was responsible for the Sofitel cancellation, and the third venue, the Claridge, was also contacted by city officials, organisers claim.

The decision to shut down the event has triggered a heated debate on constitutional rights.

Belgium's Prime Minister Alexander De Croo slammed the move as "unacceptable" and said the Belgian constitution guaranteed freedom of speech.

"We are really in the old-style communism here, basically, if you don't agree with me, you must be banned," said Farage.

Orban on X tweeted: "The last time they wanted to silence me with the police was when the Communists set them on me in 1988. We didn’t give up then and we will not give up this time either!"

A spokesperson for Britain's Prime Minister Rishi Sunak called the decision "extremely disturbing".

One of the co-hosts of the event was the Brussels office MCC, a Hungarian government-funded elite education institution seen as the breeding ground for the future Fidesz elite. MCC has made partnerships in Europe with conservative, eurosceptic think tanks and institutions and has set up offices in other European capitals to push Orban’s illiberal ideology.