On 26 August 1955, with a view to the Noordwijk Conference, Auguste Vanistendael, Secretary-General of the International Confederation of Christian Trade Unions (ICCTU), forwards to Paul-Henri Spaak, President of the Intergovernmental Conference established by the Messina Conference, a letter in which he outlines his hope that the trade unions will be invited to take part in the work of the Spaak Committee.

In February 1956, the German Iron and Steel Federation objects to further sectoral integration in Europe at the expense of the wider integration envisaged by the Six following the Messina Conference.

On 4 February 1956, Fritz Berg, President of the Federation of German Industries (BDI), forwards a note to the German Chancellor, Konrad Adenuer, in which he outlines his fear that further European integration in the nuclear field will hamper integration in the other fields identified by the Six at the end of the Messina Conference.

From 27 to 29 April 1956, at the end of its meeting in Paris, with the help of the Socialist Movement for the United States of Europe (SMUSE), the European Congress of Labour — attended by Paul-Henri Spaak, Sicco Mansholt, Guy Mollet and Jean Monnet — adopts a series of resolutions on the social objectives of the future European Economic Community (EEC).

On 5 October 1956, the German trade union weekly Welt der Arbeit invites progressive forces to support the emergence of a unified Europe as advocated by the Action Committee for the United States of Europe (ACUSE) chaired by Jean Monnet.

On 12 October 1956, the International Confederation of Christian Trade Unions (ICCTU) forwards to the Foreign Ministers of the six countries participating in the Intergovernmental Conference held at the Château de Val Duchesse a memorandum in which it emphasises the importance of involving workers in developments in the Common Market as well as the peaceful nature of Euratom.

In November–December 1956, 13 European trade unions send a letter to the chairman of the Brussels Conference and to the foreign ministers of the participating countries in which they emphasise their commitment to the social aspects of the Common Market and Euratom and request that the treaties being drawn up provide for the legitimate participation of trade unions.

On 10 December 1956, Hendrik Oosterhuis, Chairman of the Dutch Trade Union Federation and member of the Action Committee for the United States of Europe (ACUSE), sends a letter to the Foreign Ministers of the six countries participating in the Intergovernmental Conference on the Common Market and Euratom in Val Duchesse in which he emphasises the importance that he places on the association of European trade unions with the operation and social aspects of the future European Economic Community (EEC) and European Atomic Energy Community (EAEC or Euratom), in particular through the establishment of an Economic and Social Committee (ESC).

On 24 January 1957, Robert Bothereau, Secretary-General of the General Confederation of Labour-Workers’ Force (CGT-FO), stresses the importance of the future European Economic Community (EEC) and Euratom and emphasises the place of the trade unions in the structures of the two Communities.

‘A Common Market? All right, but just between the two of us.’ On 24 January 1957, in the weekly publication of the General Confederation of Labour-Workers’ Force (CGT-FO), the French cartoonist, Nitro, condemns the policy of French and German employers who are trying to exclude workers from the negotiations on and establishment of the European Economic Community (EEC).

On 25 January 1957, the Luxembourg trade union newspaper Sozialer Fortschritt publishes a note from the International Confederation of Christian Trade Unions (ICCTU) on the implications of the Common Market and Euratom.

On 25 January 1957, the Dutch Liberal daily newspaper Nieuwe Rotterdamse Courant publishes a statement made by the trade unionist Louis Major, Secretary-General of the General Federation of Belgian Labour (FGTB) and Socialist MP, who speculates about the social aspects of the future European Economic Community (EEC).

On 30 January 1957, the Netherlands free trade unions state their position on the draft Treaty establishing the European Economic Community (EEC).

On 7 February 1957, the Luxembourg Socialist daily newspaper Tageblatt reaffirms how important it is for the Socialists and the trade unions to ensure that workers’ interests are defended during the drafting of the Treaty establishing the European Economic Community (EEC).

On 21 February 1957, the Luxembourg trade union newspaper Sozialer Fortschritt publishes a memorandum from the Confederation of Christian Trade Unions on the economic and social implications of the Treaties establishing the European Economic Community (EEC) and the European Atomic Energy Community (EAEC or Euratom).

In April 1957, the German Section of the European Committee for Economic and Social Progress welcomes the signing, in Rome, of the Treaty establishing the European Economic Community (EEC) and emphasises the conditions needed for its effective operation.

On 11 April 1957, welcoming the signing on 25 March 1957 in Rome of the Treaties establishing the European Economic Community (EEC) and the European Atomic Energy Community (EAEC or Euratom), Raymond Le Bourre, Confederal Secretary of the Workers’ Force Confederation (FO), emphasises that the working class must participate in the European integration process.

At the Congress of the World Federation of Trade Unions, held in Leipzig from 4 to 15 October 1957, Benoît Frachon, French General Secretary of the General Confederation of Labour (CGT), delivers an address in which he outlines the dangers of the Common Market.

On 8 December 1957, in an article published in the French daily newspaper Le Monde, Otto Brenner, leader of the West German Metalworkers’ Union and Member of the Action Committee for the United States of Europe (ACUSE), criticises the lack of representation of trade union organisations in the institutions of the European Economic Community (EEC) and the European Atomic Energy Community (EAEC or Euratom).

In June 1956, at the third international conference organised in Brussels by the European League for Economic Cooperation (ELEC) on the economic issues surrounding the European revival, Rudolf Meimberg, professor at the University of Frankfurt and Director of the Deutsche Bank, outlines the advantages of a European common market and a customs union, particularly with regard to their social aspects.

In June 1956, the European League for Economic Cooperation (ELEC) holds its third international conference in Brussels. At the conference, Geldofph A. Kohnstamm, who works for the Arnhem-based company Algemeene Kunstzijde Unie, presents an introductory report in which he considers the possible consequences of the Common Market for the social development of European citizens.

On 6 September 1956, Maurice Faure, Junior Minister in the French Foreign Ministry and Head of the French Delegation to the Intergovernmental Conference on the Common Market and Euratom, outlines to the other national delegations present at the Château de Val Duchesse France’s position on the harmonisation of social policies and systems within the Common Market.

En 1955, le Bureau international du travail (BIT) charge un groupe d'experts d'étudier les aspects sociaux de la coopération économique européenne. Un an plus tard, les experts rendent publiques leurs conclusions.

On 1 October 1956, the Dutch Council of Ministers examines the social demands made by the French delegation to the Intergovernmental Conference on the Common Market and Euratom.

On 14 December 1956, the European League for Economic Cooperation (ELEC) adopts a resolution in order to express its support for improvements to social security through the establishment of a common market in Europe.

On 19 January 1957, the German economic journal Der Volkswirt condemns what it sees as the secretive nature of the work of the Intergovernmental Conference on the Common Market and Euratom and outlines the weaknesses of the future European Economic Community (EEC), with particular regard to social harmonisation measures.

In March 1957, La Revue Politique, the official publication of the Belgian Social Christian Party (PSC), looks at the provisions in the Treaty establishing the European Economic Community (EEC) regarding the harmonisation of salaries and social security contributions.