WARSAW was swamped by tens of thousands of protesters marching through the Polish capital at the weekend to support the European Union and condemn the conservative Law and Justice government.

The demonstrators were objecting to centralisation of authority, especially government steps to stop the Constitutional Tribunal acting as as a check on the ruling party’s power.

Marchers carrying white-and-red national flags and blue-and-yellow EU flags blew trumpets and chanted: “We say no thanks to rotten change” and “Free judge, free Poland.”

Law and Justice maintains that it has a democratic mandate for changes after decisive electoral wins last year.

Civic Platform party leader Grzegorz Schetyna, a former foreign minister, declared the event the biggest demonstration of the post-socialist era, forgetful of the huge protests by unemployment-threatened miners in the 1990s during the transition to capitalism.

“We will not let the nightmare of authoritarian rule happen,“ said Mr Schetyna.

There was a counterprotest by about 1,000 nationalists and Catholic groups, who condemned the influence of Brussels on Poland’s affairs and the more secular lifestyle associated with EU membership.

Ruling party leader Jaroslaw Kaczynski dismissed the demonstration as an expression of some groups’ dissatisfaction with the fact that his party had won the elections, saying it was “not a big problem.”

Poland wants to help reform the EU but to be “separate” on social values, he added.

The protest was organised by the neoliberal Civic Platform, which lost power last year, the Committee for the Defence of Democracy and other opposition parties.