| Country | Action | Action Date | Effective Date |
|---|
| AUSTRIA | Signature | 30/04/1956 | |
| AUSTRIA | Ratification | 21/05/1957 | |
| BELGIUM | Signature | 30/04/1956 | |
| BELGIUM | Ratification | 22/04/1960 | |
| Channel Islands | Accession | 11/01/1960 | |
| DENMARK | Signature | 30/04/1956 | |
| DENMARK | Ratification | 12/09/1957 | |
| FINLAND | Signature | 14/10/1957 | |
| FINLAND | Ratification | 06/11/1957 | |
| FRANCE | Signature | 30/04/1956 | |
| FRANCE | Ratification | 05/06/1957 | |
| GERMANY FEDERAL REPUBLIC | Signature | 30/04/1956 | |
| GERMANY FEDERAL REPUBLIC | Ratification | 11/09/1959 | |
| ICELAND | Signature | 30/04/1956 | |
| ICELAND | Ratification | 25/09/1961 | |
| IRELAND, REPUBLIC OF | Signature | 30/04/1956 | |
| IRELAND, REPUBLIC OF | Ratification | 02/08/1961 | |
| Isle of Man | Extension | 11/01/1960 | |
| Isle of Man | Accession | 11/01/1960 | |
| ITALY | Signature | 30/04/1956 | |
| LUXEMBOURG | Signature | 30/04/1956 | |
| LUXEMBOURG | Ratification | 23/12/1963 | |
| NETHERLANDS THE | Signature | 30/04/1956 | |
| NETHERLANDS THE | Ratification | 20/01/1958 | |
| NORWAY | Signature | 30/04/1956 | |
| NORWAY | Ratification | 05/08/1957 | |
| PORTUGAL | Signature | 07/05/1957 | |
| PORTUGAL | Ratification | 17/10/1958 | |
| SPAIN | Signature | 30/04/1956 | |
| SPAIN | Ratification | 30/05/1957 | |
| SWEDEN | Signature | 23/01/1957 | |
| SWEDEN | Ratification | 13/08/1957 | |
| SWITZERLAND | Signature | 30/04/1956 | |
| SWITZERLAND | Ratification | 02/04/1957 | |
| TURKEY | Signature | 30/04/1956 | |
| TURKEY | Ratification | 04/11/1958 | |
| UNITED KINGDOM | Accession | 11/01/1960 | |