All trade unions were suspended starting in 1939 with the German invasion of Poland and remained prohibited for the duration of Nazi control.
OPZZ continued to operate after the fall of the communist government and remains the largest trade union in Poland, though its membership numbers have dropped significantly from their peak in the late 1980s.
As in all countries of Central Europe also in Poland trade unions were active since the end of the 19th century, particularly in the Prussian and Austrian partition regions.
Regime trade unions became the fundamental element of workers' organisations, which was also aimed at preventing solidarity in state combines and regions.
However, this repeatedly met with violent resistance of the workers in the industrial centres, like in Poznań in 1956, in the northern coastal cities in 1970, in Radom and Ursus in 1976 as well as at the Lenin Shipyard in Gdańsk in 1980.
The most significant result was the foundation of the Independent Self- governing Trade Union ‘Solidarity’(NSZZ Solidarnosc) in August 1980, a mass organisation with almost 10 million members.
During Martial Law, which was introduced on 13 December 1981 and lasted until June 1983, Solidarnosc was banned and the controlled refoundation of trade unions dependent on state orders began.
At the beginning of 2002 a new trade union federation split away from OPZZ, namely the FZZ Forum with 515.000 members mainly from civil service, local governments, railways, energy, mines and other state-owned enterprises.
In autumn 1981 ten million people belonged to NSZZ Solidarnosc, but after its second legalization in April 1989 it did not manage to regain its previous significance and number of members.
4 Juliusz Gardawski, Declining trade union density examined, 'Foundation Institute of Public Affairs', Warsaw 2002, published in 'Eiro-Portal' (European Industrial Relations Observatory on-line).
Lech Wałęsa, the first chairman of Solidarność became president of Poland in 1990 and many trade union members held government offices and seats in Parliament and on management boards of big state-owned companies.
This led to a loss of authority of Solidarność as an institution representing workers' interests and separated it away from its grass roots members.
In the parliamentary elections of 2001 it did not manage to get over the legal hurdle of 8 per cent of votes for electoral coalitions and since then has not had a single parliamentarian in the Sejm.
The structural reforms of the nineties lead to the impoverishment of certain parts of the society, to dismissals and growing unemployment, for which not only the government but also the trade unions were blamed.
The weekly newspaper 'Tygodnik Solidarność' constantly supported the policy of PiS which governed from 2005 to 2007 with the rural interest party Self-Defence of the Republic of Poland (Samoobrona) and the extreme right-wing League of Polish Families (LPR).
Reform of structures has become a magic formula present at all congresses and in programmatic documents in many variations, but that does not result in any significant changes.
Statistics are rarely published and are extremely difficult to prepare anyway, due to the huge fragmentation and insufficient links between organisational levels.
The overwhelming part of the basic trade unions are 'plant social clubs' or even 'functional groups' for administration, sales, logistics, foremen, technicians, etc.
Some of those 'plant social clubs' function only in their own departments or sites and know only little about trade union work in other locations of the enterprise.
Cooperation in trade union networks for entire enterprises and groups of companies is only an exception and takes place with foreign, often German help.
The EU- inspired Law on Information and Consultation, passed on 7 April 2006, slowly contributes to changing this situation by means of the creation of "Employees Councils".
Trade unions, if they exist, are generally strongest on the plant or site level where the collection of membership dues takes place.
The generally conservative trade unions are often wary or even mistrustful towards consumer or environmental organisations which follow other aims and sometimes represent contradictory interests.
Some important phenomena of today's labour market like gender questions, mobbing, interest protection of employees mistreated in big chain stores, temporary work or subcontracted labour became topics of the public debate thanks to civil society, the media and ad hoc socio- political associations.
[citation needed] OPZZ belonged from 1984 till 1991 to the communist-dominated World Federation of Trade Unions (WFTU) in Prague.
In March 2006 it joined the European Trade Union Confederation after the long-standing quarrel with Solidarnosc concerning real estate was settled.
The biggest trade union in the country, the OPZZ member ZNP, belonged to the teachers' federations of the ICFTU as well as of the WCL.
[citation needed] Since September 2003 the FZZ Forum is a member of the Confederation of Free Trade Unions (Federation of Civil Servants CESI).