His release comes only two days after riot police used tear gas, water cannon and phosphorous rockets to disperse big pro-Solidarity demonstrations in Warsaw and other cities.

The freeing of the shipyard electrician will be seen by the Polish people as a sign the Communist government may be preparing to lift martial law.

It was imposed almost a year ago to curb the growing influence of the Solidarity trade union and put off the threat of armed intervention from the Soviet Union.

Remote hunting lodge

Government spokesman Jerzy Urban said Mr Walesa was being released because he was no longer considered a threat to law and order.

He revealed Mr Walesa had also written a letter to the Polish leader General Wojciech Jaruzelski seeking a "national agreement".

Since his arrest Mr Walesa has been held in isolation at a remote government hunting lodge in Arlamowo, south-east Poland, close to the Soviet border.

It is thought General Jaruzelski may have struck a deal with the Roman Catholic Church which included freeing Mr Walesa in a bid to win the support of the Polish people for a limited programme of economic and political reforms.

He has already set a date in June for the Polish-born Pope John Paul II's visit to Poland. The Pope has always insisted the visit could only be made if there was an end to martial law.

Government sources say there is a possibility Mr Walesa will be able to see a senior official, perhaps the Trade Union Minister Stanislaw Ciosek, at the weekend before travelling to his home in Gdansk.

But they have made clear Mr Walesa will be interned again if he seeks to oppose the Government.

Mr Walesa rose to prominence as one of the leaders of the shipyard workers in Gdansk.

In 1980 he was one of the key men behind the Gdansk shipyard strike which gave rise to a wave of disputes over much of the country. The primary demands were for workers' rights.

The authorities were forced to give in and negotiate with Mr Walesa. Under the terms of the Gdansk Agreement of 31 August 1980, workers were given the right to strike and to organise their own independent union, Solidarity.

The Catholic Church supported Mr Walesa's aims and he was received by the Pope in the Vatican in 1981.

But the country's brief period of relative freedom ended with the declaration of martial law in December 1981 and the suspension of Solidarity.

	E-mail this story to a friend