Hundreds of thousands of people have marched through central Warsaw to protest against Poland’s rightwing populist government before a delicately poised election due in the autumn. The Law and Justice (PiS) party came to power in 2015, since when it has eroded democratic norms, attacked the independent judiciary and launched campaigns against the LGBTQ+ community and reproductive rights. “We’re half a million here, it’s a record,” said Donald Tusk, the former prime minister who leads the Civil Platform opposition grouping. He said the march on Sunday had been the biggest political gathering since Poland regained independence after the communist period. There was no official confirmation of the size of the rally, though Warsaw’s city hall also gave a 500,000 estimate, and central streets thronged with crowds of protesters. The city’s metro was overwhelmed as people converged on the centre. Many people waved Polish or EU flags and the mood was defiant but often festive. “The whole of Poland, the whole of Europe and the whole world sees how strong we are and how we are ready to fight for democracy and freedom again, like we did 30, 40 years ago,” Tusk told the crowds at the start of the rally. Tusk, who served two terms as Poland’s prime minister from 2007 until 2014, has returned to national politics after a five-year stint as president of the European Council. The march was convened to mark the 34th anniversary of an election in 1989, won by a group linked to the Solidarity trade union movement, which proved a vital moment in ending communist rule in Poland. Although convened by Civil Platform, the march brought numerous opposition groupings together, and banners among the crowd called for everything from trans rights to trade union representation. “Thirty-four years ago we were all together and there was a sense of community, and we have to recover this sense of community and transform our anger into strength,” said Rafał Trzaskowski, the liberal mayor of Warsaw. Also present at the rally was Lech Wałęsa, the shipyard worker who emerged as a leader of the solidarity movement and later became Poland’s president. He is now a staunch critic of PiS. PiS has won popularity for policies that have led to increased social spending. Russia’s invasion of Ukraine has also shored up the party’s support, as well as muting some international criticism of its policies as Poland has emerged as a vital pillar of the western alliance in support of Ukraine. Polls suggest that neither PiS nor Tusk’s Civic Platform are likely to gain enough votes to form a government alone, so the election outcome could hinge on how smaller parties fare and who is able to form a workable coalition. The opposition has been galvanised in recent days by the passing of a controversial law that would allow a government commission to ban people from public office if it believes they were agents of Russian influence. It has been nicknamed “Lex Tusk” as it is widely seen as targeting the opposition leader. The law was signed by President Andrzej Duda last week, although he almost immediately suggested amendments to it after a storm of criticism that it was unconstitutional and a pretext to launch a political witch-hunt. “The law is against Tusk but we can all be targeted by this law, because they will not hesitate to use it against anyone,” said the lawyer and rights activist Sylwia Gregorczyk-Abram before the rally. “It is the culmination of the authoritarian system developed in Poland over the past eight years. We are now at a crossroads between being an authoritarian and a democratic country.” Although there were marches in cities across Poland, many people from around the country travelled to Warsaw to be at the main march. “I’ve always come to protests, but this time there are some others who haven’t been before, because people see that things are getting really serious now,” said Marzena, 48, who had arrived on a coach with about 50 others from the town of Giżycko in northern Poland. Zuzanna, a 20-year-old finance and accounting student from the city of Bytom in Silesia, had travelled for four hours by bus with her grandmother to attend the rally, her first ever protest. “PiS has been here for eight years,” she said. “If they win again, Poland will be ruined and we will be Hungary or China.” She was carrying a poster commemorating a woman who died of septic shock last year after doctors refused to perform an abortion when the foetus’s heart stopped beating. “I love Poland but if they win again I don’t think it will be possible to live here any more,” she said. Zuzanna’s grandmother Krystyna, 67, said she was an outlier among friends her age, who were mostly government supporters and approved of the increased social benefits in recent years. She said: “What use is money to me if my granddaughter will leave the country?” While the mood on Sunday was mostly good-natured, there were flashes of real anger on some of the signs protesters had made, or in their chants. As the crowds passed the presidential palace, parts of the crowd chanted “You will be imprisoned” in the direction of the building. Rhetoric in the deeply polarised country is likely to intensify in the months before the election. Jarosław Kaczyński, the chair of PiS, claimed last week that an opposition vote would mean “the end of Poland”. On Sunday, Tusk raised the possibility of pursuing legal action against government figures after a potential future election win. “Those who commit evil will be held accountable and there will be no lenience,” he said.