Thousands gathered in Solidarity Square

Solidarity's founder, Lech Walesa, was joined by guests including Polish Prime Minister Jerzy Buzek and the former UK Prime Minister Margaret Thatcher in laying wreaths at a monument to shipyard workers killed by security forces during a strike in 1970.

A crowd of 2,000 to 3,000 people gathered on Gdansk's Solidarity Square as Mr Walesa and other dignitaries laid wreaths at the monument.

About 250 workers from the town's shipyards, where Solidarity was born, were also present, wearing hard hats and workers' overalls.

Hundreds of bright Solidarity banners with their trademark red-and-white colours were flown by union supporters.

Out of touch

Mr Walesa told Polish television of his satisfaction that the movement had successfully changed the image of the country and contributed to the fall of communism throughout Eastern Europe.

At its height, Solidarity enjoyed huge support

But he also voiced concern over the pain caused by economic reform.

Although the Polish economy has shown consistently high growth rates, for many life is hard and the minority Solidarity government is unpopular.

One former leading light of the movement, Bronislaw Geremek, has said Solidarity lost touch with ordinary Poles and failed to explain its policies.

Giving thanks

After the wreath-laying ceremony, the Primate of Poland, Cardinal Jozef Glemp, held a holy mass and said Solidarity had achieved a miracle by uniting Poles against the Communist regime.

Former UK Prime Minister Margaret Thatcher attended the ceremony

The celebrations will be rounded off with a rock concert held in the Gdansk shipyards.

Many groups which supported Solidarity during the 1980s will perform.

The day marks exactly 20 years from the day when Solidarity was recognised by the communist regime under the Gdansk Accord, which also granted other political freedoms.

However, the anniversary celebrations have not met with particular public interest in the country, which is facing increasing economic difficulties.