Former Fidesz insider Peter Magyar has stepped up as challenger to Viktor Orbán, Hungary’s longest-serving prime minister on record, after organising the largest mass demonstration since the country’s transition to democracy in 1989-1990.

"Change has started that can't be stopped," he told supporters filling the square and nearby streets in front of the parliament building in Budapest's main square.

The demonstration is a huge defeat for Fidesz, as its attempt to discredit Magyar was futile, bit it is also a huge slap in the face for the opposition, which for years has been unable to gather a crowd similar to Saturday's rally.

In less than two months since bursting into the limelight, 42-year-old Magyar – the ex-husband of former Justice Minister Judit Varga, and a businessman and lawyer close to the ruling Fidesz party – has shaken up the political landscape and given hope to hundreds of thousands of Hungarians who had almost given up hope that the radical rightwing Orban regime could be toppled.

Since he made his debut in politics, Magyar has positioned himself as a centrist, targeting those who have grown tired of the political elite, from the left to the right.

A recent poll by the Budapest-based Republikon Institute found that his party, if formally formed, would be the third most popular in the country, with 15%. According to the survey, a third of his supporters come from the undecided, which hit record levels recently, and he managed to lure 5% of active Fidesz supporters, but he has managed to draw in many apolitical voters as well. He also swayed many opposition voters, according to Republikon.

Magyar’s presence in politics could become a serious headache for  Orban. The ruling party has lost its stamina and its ability to control the narrative. It has lurched from one crisis to another in the last two months.

The Fidesz paedophile pardon scandal in early February rocked Hungarian politics when it was revealed that President Katalin Novák granted a pardon to the deputy head of an orphanage who covered up the sexual abuse of children committed by his boss.

The scandal led to the fall from grace of Varga, who reportedly refused the pardon, but eventually countersigned it after Novak okayed it. There is still no answer as to who lobbied for the clemency, but critics of Orban claim the prime minister had the final say.

Hungary is facing its biggest legal, political, moral, and economic crisis of the last 30 years, and people feel they have had enough, Magyar told local media after the rally. He tried to downplay his role saying "I may be the spark that started the fire".

Despite the unseasonably hot weather, an estimated 200,000-250,000 people took to the streets in Budapest from all parts of Hungary. Many arrived from European cities and the United States just for this occasion. The Facebook post of Magyar was buzzing ahead of the demonstration. People were offering car-sharing and lodgings for those arriving from the countryside.

According to observers, the size of the demonstration matches that of the June 27, 1988, mass protest in Heroes Square against Nicolae Ceausescu's plans to destroy villages of ethnic Hungarians in Romania, seen as one of the most important events in the fall of Communism in Hungary.

The rally was the second one in two weeks by Magyar, who made a successful debut in the political arena on the national holiday on March 15, where he announced plans to run in the EP and local government elections on June 9.

Due to time constraints, Magyar has no chance of setting up his own party before that time, but he is involved in talks with small, fringe parties that he could use as a proxy. He told independent media that he will name that party at his next rally scheduled for May 5.

By 3 pm, the iconic square in front of parliament was filled, and the crowd spilled over to nearby streets. Many carried red-white-green flags that reminded observers of a rally organised by Fidesz, but analysts rightfully pointed out it was a clear attempt to take back the symbols expropriated by the ruling party.

Magyar and his team also carried a big banner in the march through central Budapest, which was also reminiscent of Fidesz rallies. The caption on the banner read: "Do not be afraid". Some other protesters carried signs bearing the names of their hometowns.

The two-hour rally began with a popular actor reading out personal stories of Hungarians living abroad. An estimated 500,000 have left Hungary since Orbán came to power in 2010 because of his regime's corruption, nepotism, the demise of education, and the country's democratic backsliding.

The independent mayor of a small town accused local representatives of Hungary’s largest opposition party DK of collaborating with Fidesz, a message also shared by Magyar in earlier interviews in which he said that Hungary’s political elite must be renewed. A representative of the Reformed Church said leaders of the church bear responsibility for the moral decline in Hungary, referring to Bishop Zoltán Balogh, who openly acknowledged that as an advisor to Novák, he supported the pardon of the deputy head of the children’s home.

Magyar, who stepped up to the podium to the beats of Europe’s "Final Countdown" hit, began his speech by saying: "Remember this day, April 6, 2024, because from now on, nothing will be the same."

"In just a few weeks, the message of hope has reached the farthest corners of the country. We did something unprecedented since the change of regime," Magyar said as he made the case for a European-facing and meritocratic Hungary. "Change has started, which can't be stopped," he declared. "Step by step, brick by brick, we are taking back our homeland and building a new country, a sovereign, modern, European Hungary."

Magyar lashed out at government propaganda machines and the lack of independence of media and the prosecutor's office as he presented accusations of corruption at the highest levels of government.

"More than 20 years have passed with elected leaders inciting Hungarians against each other, but now we are putting an end to this," he said, calling for everyone from right to left and liberal to work together to replace the current political elite.

"The current government has steered the country into the biggest political, legal, and moral crisis of the last 30 years. Give power back to the people, take political and legal responsibility," he said. He turned to the representatives of the ruling party, saying it would soon be too late to change sides.

The results of the European Parliament elections will be the first nail in the coffin of the regime, he stressed. Magyar said applications will be open to pick candidates for the EP elections.

"You may ask if I still have some nuclear bomb," he asked the crowd, referring to damaging inside information against senior government officials. "We are the atomic bomb, the Hungarian people."

Magyar also urged his supporters to be active in the new movement called Arise Hungarians (Talpra Magyarok) and said that everyone must move to bring about change. "We must take back our villages and towns," he said.

Many had expected Magyar to name his proxy party, but that may be announced at the next rally convened for May 5.

Speaking to reporters after the rally, Magyar said that it would be a great setback for Fidesz if it had only 40-45% of the vote in the EP election, where the party had done over 50% in the past two elections. He said the slide of Fidesz has begun and associating with the ruling party "has become cringe".

He told independent media that he had been approached by Fidesz officials. He expects defections to pick up from the ruling party after the election.

Magyar has identified himself as a proud conservative hailing from a lineage of two generations of lawyers. His grandfather was a renowned professor and a television personality and counted Ferenc Madl, President of Hungary between 2000 and 2005, as his godfather.

Since entering public life, Magyar has been leveling accusations against the government, touching on issues from corruption to the machinations of its propaganda machine.

In late March, he presented an audio recording of a conversation with his wife, where Varga makes some serious comments about the operation of the prosecution in a high-profile corruption case and admitted that government officials tampered with evidence.

In the conversation taped secretly in their home just before they filed for divorce, Varga said that Antal Rogan (head of the Prime Minister’s Cabinet Office, head of propaganda, and Hungary’s intelligence services) and his people suggested to the prosecutors what should be removed from the evidence in the corruption case involving former Justice Ministry deputy Pal Volner and Gyorgy Schadl, the former head of the bailiffs' association.

Varga was unhappy with the work of Hungary’s chief prosecutor, Peter Polt, for allowing the investigation to move forward in the case and she is heard telling his husband that Volner allegedly continued to accept bribes even as he was warned of the secret surveillance in the case, which again raises questions of serious breaches of the law.

A day before Magyar testified to the prosecutor's office, presenting the evidence, he told local media that before he started the recording with his former wife, she was saying "This is a mafia government that you can't get out of". In early February, pro-Orban media attempted to downplay Magyar’s role and his allegations of corruption and nepotism but after he presented the secret audio and announced the launch of a party, he became the target of an unprecedented smear campaign.

His former wife broke silence in mid-March, accusing Magyar of verbal and physical abuse. Orban-loyal media ran hundreds of stories in just the last few days to discredit the emerging star of the opposition. In an earlier interview, Magyar confirmed reports that the Karmelita (Orban’s office) forbade them to divorce before the 2022 elections.

Magyar's success can be attributed partly to the wide disillusionment with the political establishment, political scientists said, which has been unprecedented since the reign of Fidesz began.

"He is a former insider who can say things that could be damaging to the regime as he knows how the power machine operates," said one analyst. This was an unprecedented experience for most people in the crowd and participants felt a profound sense of freedom in openly voicing their dissatisfaction with the government, commented political scientist Laszlo Keri, a former teacher of most of today’s leaders in Fidesz during their university years in the 1980s.