Political organisations
| Name | Type | Notes |
|---|---|---|
| Church Army | Religious | |
| Church Assembly | Religious | forerunner to General Synod |
| Church Missionary Society | Religious | |
| Church of Scotland | Religious | |
| Cinematograph Exhibitors' Association | Trade group | |
| Civil Rights Association | Pressure group | |
| Clergy Defence Association | Pressure group | |
| Clyde Workers Committee | Trade group | |
| CMWU | Party group | Cons Womens' Union |
| Coalition for Peace through Security | Peace movement | |
| Coal Merchants' Federation of Great Britain | Trade group | |
| Cold Storage and Ice Association | Trade group | |
| Common Market Campaign | Pressure group | |
| Common Market Safeguards Committee | Pressure group | |
| Commonwealth | International body | |
| Commonwealth Institute | Miscellaneous | |
| Compass | Pressure group | |
| Conference of Churches of Christ | Miscellaneous | |
| Congregationalist | Religious | |
| Congregational Union of England and Wales | Religious |