Trade unions
C
| Full Name | Short Name | Notes |
|---|---|---|
| Card Setting Machine Tenters Society | CSMTS | |
| Ceramic and Allied Trades Union | CATU | |
| Chainmakers and Strikers' Association | CSA | |
| Chartered Society of Physiotherapy | CSP | |
| Chemical Workers' Union | ChWU | |
| Civil and Public Services Association | CSPA | Renamed from the Civil Service Clerical Association in 1969. Merged with the Public Services, Tax and Commerce Union in 1998 to form the Public and Commercial Services Union. |
| Civil Service Clerical Association | CSCA | Formed in 1921, from a merger of the Civil Service Clerical Union and the Clerical Officers' Association. Renamed in 1969 as the Civil and Public Services Association. |
| Clerical and Administrative Workers' Union | CAWU | |
| Communication Workers Union | CWU | |
| Community | CTU | Formed 2004. |
| Community and District Nursing Association | CDNA | |
| Community and Youth Workers' Union | CYWU | |
| Confederation of Engineering and Shipbuilding Trades | CEST | |
| Confederation of Health Service Employees | COHSE | |
| Connect | Connect | |
| Constructional Engineering Union | CEU |